Author name code: ramsey
ADS astronomy entries on 2022-09-14
author:"Ramsey, Lawrence W." OR author:"Ramsey, Larry W." 
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Title: TOI-3757 b: A Low-density Gas Giant Orbiting a
    Solar-metallicity M Dwarf
Authors: Kanodia, Shubham; Libby-Roberts, Jessica; Cañas, Caleb I.;
   Ninan, Joe P.; Mahadevan, Suvrath; Stefansson, Gudmundur; Lin, Andrea
   S. J.; Jones, Sinclaire; Monson, Andrew; Parker, Brock A.; Kobulnicky,
   Henry A.; Swaby, Tera N.; Powers, Luke; Beard, Corey; Bender, Chad F.;
   Blake, Cullen H.; Cochran, William D.; Dong, Jiayin; Diddams, Scott A.;
   Fredrick, Connor; Gupta, Arvind F.; Halverson, Samuel; Hearty, Fred;
   Logsdon, Sarah E.; Metcalf, Andrew J.; McElwain, Michael W.; Morley,
   Caroline; Rajagopal, Jayadev; Ramsey, Lawrence W.; Robertson, Paul;
   Roy, Arpita; Schwab, Christian; Terrien, Ryan C.; Wisniewski, John;
   Wright, Jason T.
Bibcode: 2022AJ....164...81K
Altcode: 2022arXiv220307178K
  We present the discovery of a new Jovian-sized planet, TOI-3757
  b, the lowest-density transiting planet known to orbit an M dwarf
  (M0V). This planet was discovered around a solar-metallicity M dwarf,
  using Transiting Exoplanet Survey Satellite photometry and confirmed
  with precise radial velocities from the Habitable-zone Planet Finder
  (HPF) and NEID. With a planetary radius of 12.0 ${}_{-0.5}^{+0.4}$ R
  <SUB>⊕</SUB> and mass of 85.3 ${}_{-8.7}^{+8.8}$ M <SUB>⊕</SUB>, not
  only does this object add to the small sample of gas giants (~10) around
  M dwarfs, but also its low density ( $\rho ={0.27}_{-0.04}^{+0.05}$
  g cm<SUP>-3</SUP>) provides an opportunity to test theories of planet
  formation. We present two hypotheses to explain its low density; first,
  we posit that the low metallicity of its stellar host (~0.3 dex lower
  than the median metallicity of M dwarfs hosting gas giants) could have
  played a role in the delayed formation of a solid core massive enough
  to initiate runaway accretion. Second, using the eccentricity estimate
  of 0.14 ± 0.06, we determine it is also plausible for tidal heating to
  at least partially be responsible for inflating the radius of TOI-3757b
  b. The low density and large scale height of TOI-3757 b makes it an
  excellent target for transmission spectroscopy studies of atmospheric
  escape and composition (transmission spectroscopy measurement of ~
  190). We use HPF to perform transmission spectroscopy of TOI-3757 b
  using the helium 10830 Å line. Doing this, we place an upper limit
  of 6.9% (with 90% confidence) on the maximum depth of the absorption
  from the metastable transition of He at ~10830 Å, which can help
  constraint the atmospheric mass-loss rate in this energy-limited regime.

Title: The Active Chromospheres of Lithium-Rich Red Giant Stars
Authors: Sneden, Christopher; Afsar, Melike; Bozkurt, Zeynep; Adamow,
   Monika; Mallick, Anohita; Reddy, Bacham E.; Janowiecki, Steven;
   Mahadevan, Suvrath; Bowler, Brendan P.; Hawkins, Keith; Lind, Karin;
   Dupree, Andrea K.; Ninan, Joe P.; Nagarajan, Neel; Bocek Topcu,
   Gamze; Froning, Cynthia S.; Bender, Chad F.; Terrien, Ryan; Ramsey,
   Lawrence W.; Mace, Gregory N.
Bibcode: 2022arXiv220905941S
Altcode:
  We have gathered near-infrared $zyJ$-band high resolution spectra
  of nearly 300 field red giant stars with known lithium abundances
  in order to survey their \species{He}{i} $\lambda$10830 absorption
  strengths. This transition is an indicator of chromospheric activity
  and/or mass loss in red giants. The majority of stars in our sample
  reside in the red clump or red horizontal branch based on their
  $V-J,M_V$ color-magnitude diagram and their Gaia \teff, \logg\
  values. Most of our target stars are Li-poor in the sense of having
  normally low Li abundances, defined here as \eps{Li}~$<$~1.25. Over
  90\% of these Li-poor stars have weak $\lambda$10830 features. But
  more than half of the 83 Li-rich stars (\eps{Li}~$>$~1.25) have strong
  $\lambda$10830 absorptions. These large $\lambda$10830 lines signal
  excess chromospheric activity in Li-rich stars; there is almost no
  indication of significant mass loss. The Li-rich giants also may have a
  higher binary fraction than do Li-poor stars, based on their astrometric
  data. It appears likely that both residence on the horizontal branch
  and present or past binary interaction play roles in the significant
  Li-He connection established in this survey.

Title: TOI-3714 b and TOI-3629 b: Two Gas Giants Transiting M Dwarfs
    Confirmed with the Habitable-zone Planet Finder and NEID
Authors: Cañas, Caleb I.; Kanodia, Shubham; Bender, Chad F.;
   Mahadevan, Suvrath; Stefánsson, Guđhmundur; Cochran, William D.;
   Lin, Andrea S. J.; Hwang, Hsiang-Chih; Powers, Luke; Monson, Andrew;
   Green, Elizabeth M.; Parker, Brock A.; Swaby, Tera N.; Kobulnicky,
   Henry A.; Wisniewski, John; Gupta, Arvind F.; Everett, Mark E.;
   Jones, Sinclaire; Anjakos, Benjamin; Beard, Corey; Blake, Cullen H.;
   Diddams, Scott A.; Dong, Zehao; Fredrick, Connor; Hakemiamjad, Elnaz;
   Hebb, Leslie; Libby-Roberts, Jessica E.; Logsdon, Sarah E.; McElwain,
   Michael W.; Metcalf, Andrew J.; Ninan, Joe P.; Rajagopal, Jayadev;
   Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Ruhle, Jacob;
   Schwab, Christian; Terrien, Ryan C.; Wright, Jason T.
Bibcode: 2022AJ....164...50C
Altcode: 2022arXiv220109963C
  We confirm the planetary nature of two gas giants discovered by the
  Transiting Exoplanet Survey Satellite to transit M dwarfs. TOI-3714
  (V = 15.24, J = 11.74) is an M2 dwarf hosting a hot Jupiter (M <SUB>
  p </SUB> = 0.70 ± 0.03 M <SUB> J </SUB> and R <SUB> p </SUB> = 1.01
  ± 0.03 R <SUB> J </SUB>) on an orbital period of 2.154849 ± 0.000001
  days with a resolved white dwarf companion. TOI-3629 (V = 14.63, J =
  11.42) is an M1 dwarf hosting a hot Jupiter (M <SUB> p </SUB> = 0.26
  ± 0.02 M <SUB> J </SUB> and R <SUB> p </SUB> =0.74 ± 0.02 R <SUB>
  J </SUB>) on an orbital period of ${3.936551}_{-0.000006}^{+0.000005}$
  days. We characterize each transiting companion using a combination
  of ground-based and space-based photometry, speckle imaging, and
  high-precision velocimetry from the Habitable-zone Planet Finder and
  the NEID spectrographs. With the discovery of these two systems, there
  are now nine M dwarfs known to host transiting hot Jupiters. Among
  this population, TOI-3714 b (T <SUB>eq</SUB> = 750 ± 20 K and TSM
  = 98 ± 7) and TOI-3629 b (T <SUB>eq</SUB> = 690 ± 20 K and TSM =
  80 ± 9) are warm gas giants amenable to additional characterization
  with transmission spectroscopy to probe atmospheric chemistry and,
  for TOI-3714, obliquity measurements to probe formation scenarios.

Title: Overview and Current Status of the NEID Data Reduction Pipeline
Authors: Bender, Chad; Ninan, Joe; Terrien, Ryan; Roy, Arpita; Esplin,
   Taran; Kaplan, Kyle; Cañas, Caleb; Fulton, Benjamin; Gupta, Arvind;
   Halverson, Samuel; Kanodia, Shubham; Laher, Russ; Lin, Andrea; Salazar
   Rivera, Noah; Blake, Cullen; Diddams, Scott; Gong, Qian; Hearty,
   Frederick; Li, Dan; Logsdon, Sarah; Lubar, Emily; Mahadevan, Suvrath;
   McElwain, Michael; Monson, Andrew; Nitroy, Colin; Rajagopal, Jayadev;
   Ramsey, Lawrence; Robertson, Paul; Schwab, Christian; Stefansson,
   Gudmundur; Wright, Jason
Bibcode: 2022AAS...24040101B
Altcode:
  The NEID precision radial velocity spectrometer at the 3.5-m WIYN
  Observatory on Kitt Peak began full science operations in summer
  2021 and since then has been producing routine data for a wide range
  of scientific programs. These include nighttime observations for GO
  programs led by PIs across the astronomy community and the GTO program
  led by the NEID instrument team, as well as the Sun-as-a-star program
  which uses the NEID solar telescope during daytime hours. Data from
  these programs are automatically processed by the NEID Data Reduction
  Pipeline (DRP), which was developed by the NEID instrument team and
  is operated by the NASA Exoplanet Science Center. The DRP processes
  raw, uncalibrated two-dimensional images from the spectrometer into
  fully calibrated, one-dimensional spectra. It then derives radial
  velocities, telluric absorption models, stellar activity metrics, and
  other high-level products, and provides these to end users. In stellar
  targets with particularly low levels of activity, the DRP has retrieved
  radial velocities at the 30 cm/s level. The DRP has also demonstrated
  the ability to successfully process targets well outside of the prime
  NEID parameter space of main sequence FGK stars, including red M-dwarfs,
  observations with low signal-to-noise, solar-system targets, and a
  variety of other astrophysical objects. In this presentation, we will
  describe the methodology and algorithms behind the DRP, as well as the
  data products that are produced and available. We will also provide
  details of DRP upgrades that have been implemented subsequent to the
  original release in June 2021, and plans for future improvements.

Title: The Warm Neptune GJ 3470b Has a Polar Orbit
Authors: Stefànsson, Guđmundur; Mahadevan, Suvrath; Petrovich,
   Cristobal; Winn, Joshua N.; Kanodia, Shubham; Millholland, Sarah
   C.; Maney, Marissa; Cañas, Caleb I.; Wisniewski, John; Robertson,
   Paul; Ninan, Joe P.; Ford, Eric B.; Bender, Chad F.; Blake, Cullen
   H.; Cegla, Heather; Cochran, William D.; Diddams, Scott A.; Dong,
   Jiayin; Endl, Michael; Fredrick, Connor; Halverson, Samuel; Hearty,
   Fred; Hebb, Leslie; Hirano, Teruyuki; Lin, Andrea S. J.; Logsdon,
   Sarah E.; Lubar, Emily; McElwain, Michael W.; Metcalf, Andrew J.;
   Monson, Andrew; Rajagopal, Jayadev; Ramsey, Lawrence W.; Roy, Arpita;
   Schwab, Christian; Schweiker, Heidi; Terrien, Ryan C.; Wright, Jason T.
Bibcode: 2022ApJ...931L..15S
Altcode: 2021arXiv211101295S
  The warm Neptune GJ 3470b transits a nearby (d = 29 pc) bright
  slowly rotating M1.5-dwarf star. Using spectroscopic observations
  during two transits with the newly commissioned NEID spectrometer
  on the WIYN 3.5 m Telescope at Kitt Peak Observatory, we model the
  classical Rossiter-McLaughlin effect, yielding a sky-projected
  obliquity of $\lambda ={98}_{-12}^{+15\ \circ }$ and a $v\sin
  i={0.85}_{-0.33}^{+0.27}\,\mathrm{km}\,{{\rm{s}}}^{-1}$ . Leveraging
  information about the rotation period and size of the host star,
  our analysis yields a true obliquity of $\psi ={95}_{-8}^{+9\
  \circ }$ , revealing that GJ 3470b is on a polar orbit. Using
  radial velocities from HIRES, HARPS, and the Habitable-zone
  Planet Finder, we show that the data are compatible with a
  long-term radial velocity (RV) slope of $\dot{\gamma }=-0.0022\pm
  0.0011\,{\rm{m}}\,{{\rm{s}}}^{-1}\,{\mathrm{day}}^{-1}$ over a baseline
  of 12.9 yr. If the RV slope is due to acceleration from another
  companion in the system, we show that such a companion is capable of
  explaining the polar and mildly eccentric orbit of GJ 3470b using
  two different secular excitation models. The existence of an outer
  companion can be further constrained with additional RV observations,
  Gaia astrometry, and future high-contrast imaging observations. Lastly,
  we show that tidal heating from GJ 3470b's mild eccentricity has most
  likely inflated the radius of GJ 3470b by a factor of ~1.5-1.7, which
  could help account for its evaporating atmosphere.

Title: Observing the Sun as a Star: Design and Early Results from
    the NEID Solar Feed
Authors: Lin, Andrea S. J.; Monson, Andrew; Mahadevan, Suvrath; Ninan,
   Joe P.; Halverson, Samuel; Nitroy, Colin; Bender, Chad F.; Logsdon,
   Sarah E.; Kanodia, Shubham; Terrien, Ryan C.; Roy, Arpita; Luhn,
   Jacob K.; Gupta, Arvind F.; Ford, Eric B.; Hearty, Fred; Laher, Russ
   R.; Hunting, Emily; McBride, William R.; Salazar Rivera, Noah Isaac;
   Rajagopal, Jayadev; Wolf, Marsha J.; Robertson, Paul; Wright, Jason T.;
   Blake, Cullen H.; Cañas, Caleb I.; Lubar, Emily; McElwain, Michael
   W.; Ramsey, Lawrence W.; Schwab, Christian; Stefansson, Gudmundur
Bibcode: 2022AJ....163..184L
Altcode: 2021arXiv211205711L
  Efforts with extreme-precision radial velocity (EPRV) instruments
  to detect small-amplitude planets are largely limited, on many
  timescales, by the effects of stellar variability and instrumental
  systematics. One avenue for investigating these effects is the use
  of small solar telescopes which direct disk-integrated sunlight to
  these EPRV instruments, observing the Sun at high cadence over months
  or years. We have designed and built a solar feed system to carry out
  "Sun-as-a-star" observations with NEID, a very high precision Doppler
  spectrometer recently commissioned at the WIYN 3.5 m Telescope at
  Kitt Peak National Observatory. The NEID solar feed has been taking
  observations nearly every day since 2020 December; data is publicly
  available at the NASA Exoplanet Science Institute NEID Solar Archive:
  https://neid.ipac.caltech.edu/search_solar.php. In this paper, we
  present the design of the NEID solar feed and explanations behind our
  design intent. We also present early radial velocity (RV) results
  which demonstrate NEID's RV stability on the Sun over 4 months of
  commissioning: 0.66 m s<SUP>-1</SUP> rms under good sky conditions
  and improving to 0.41 m s<SUP>-1</SUP> rms under best conditions.

Title: Rotational Modulation of Spectroscopic Zeeman Signatures in
    Low-mass Stars
Authors: Terrien, Ryan C.; Keen, Allison; Oda, Katy; Parts(they/them),
   Winter; Stefánsson, Guðmundur; Mahadevan, Suvrath; Robertson, Paul;
   Ninan, Joe P.; Beard, Corey; Bender, Chad F.; Cochran, William D.;
   Cunha, Katia; Diddams, Scott A.; Fredrick, Connor; Halverson, Samuel;
   Hearty, Fred; Ickler, Adam; Kanodia, Shubham; Libby-Roberts, Jessica
   E.; Lubin, Jack; Metcalf, Andrew J.; Olsen, Freja; Ramsey, Lawrence
   W.; Roy, Arpita; Schwab, Christian; Smith, Verne V.; Turner, Ben
Bibcode: 2022ApJ...927L..11T
Altcode: 2022arXiv220111288T
  Accurate tracers of the stellar magnetic field and rotation are
  cornerstones for the study of M dwarfs and for reliable detection and
  characterization of their exoplanetary companions. Such measurements
  are particularly challenging for old, slowly rotating, fully convective
  M dwarfs. To explore the use of new activity and rotation tracers,
  we examined multiyear near-infrared (NIR) spectroscopic monitoring of
  two such stars-GJ 699 (Barnard's Star) and Teegarden's Star-carried
  out with the Habitable-zone Planet Finder spectrograph. We detected
  periodic variations in absorption line widths across the stellar
  spectrum, with higher amplitudes toward longer wavelengths. We
  also detected similar variations in the strength and width of
  the 12435.67 Å neutral potassium (K I) line, a known tracer of
  the photospheric magnetic field. Attributing these variations to
  rotational modulation, we confirm the known 145 ± 15 day rotation
  period of GJ 699, and measure the rotation period of Teegarden's Star
  to be 99.6 ± 1.4 days. Based on simulations of the K I line and the
  wavelength dependence of the line-width signal, we argue that the
  observed signals are consistent with varying photospheric magnetic
  fields and the associated Zeeman effect. These results highlight the
  value of detailed line profile measurements in the NIR for diagnosing
  stellar magnetic field variability. Such measurements may be pivotal for
  disentangling activity and exoplanet-related signals in spectroscopic
  monitoring of old, low-mass stars.

Title: An Eccentric Brown Dwarf Eclipsing an M dwarf
Authors: Cañas, Caleb I.; Mahadevan, Suvrath; Bender, Chad F.;
   Salazar Rivera, Noah Isaac; Monson, Andrew; Beard, Corey; Lubin, Jack;
   Robertson, Paul; Gupta, Arvind F.; Cochran, William D.; Fredrick,
   Connor; Hearty, Fred; Jones, Sinclaire; Kanodia, Shubham; Lin,
   Andrea S. J.; Ninan, Joe P.; Ramsey, Lawrence W.; Schwab, Christian;
   Stefánsson, Guđmundur
Bibcode: 2022AJ....163...89C
Altcode: 2021arXiv211203959C
  We report the discovery of an M = 67 ± 2M <SUB>J</SUB> brown
  dwarf transiting the early M dwarf TOI-2119 on an eccentric orbit
  (e = 0.3362 ± 0.0005) at an orbital period of 7.200861 ± 0.000005
  days. We confirm the brown dwarf nature of the transiting companion
  using a combination of ground-based and space-based photometry
  and high-precision velocimetry from the Habitable-zone Planet
  Finder. Detection of the secondary eclipse with TESS photometry
  enables a precise determination of the eccentricity and reveals the
  brown dwarf has a brightness temperature of 2100 ± 80 K, a value
  which is consistent with an early L dwarf. TOI-2119 is one of the most
  eccentric known brown dwarfs with P &lt; 10 days, possibly due to the
  long circularization timescales for an object orbiting an M dwarf. We
  assess the prospects for determining the obliquity of the host star to
  probe formation scenarios and the possibility of additional companions
  in the system using Gaia EDR3 and our radial velocities.

Title: High-resolution Near-infrared Spectroscopy of a Flare around
    the Ultracool Dwarf vB 10
Authors: Kanodia, Shubham; Ramsey, Lawrence W.; Maney, Marissa;
   Mahadevan, Suvrath; Cañas, Caleb I.; Ninan, Joe P.; Monson, Andrew;
   Kowalski, Adam F.; Goumas, Maximos C.; Stefansson, Gudmundur;
   Bender, Chad F.; Cochran, William D.; Diddams, Scott A.; Fredrick,
   Connor; Halverson, Samuel; Hearty, Fred; Janowiecki, Steven; Metcalf,
   Andrew J.; Odewahn, Stephen C.; Robertson, Paul; Roy, Arpita; Schwab,
   Christian; Terrien, Ryan C.
Bibcode: 2022ApJ...925..155K
Altcode: 2021arXiv211114647K
  We present high-resolution observations of a flaring event in the
  M8 dwarf vB 10 using the near-infrared Habitable-zone Planet Finder
  (HPF) spectrograph on the Hobby-Eberly Telescope. The high stability of
  HPF enables us to accurately subtract a vB 10 quiescent spectrum from
  the flare spectrum to isolate the flare contributions and study the
  changes in the relative energy of the Ca II infrared triplet, several
  Paschen lines, the He λ10830 triplet lines, and to select iron and
  magnesium lines in HPF's bandpass. Our analysis reveals the presence
  of a red asymmetry in the He λ10830 triplet, which is similar to
  signatures of coronal rain in the Sun. Photometry of the flare derived
  from an acquisition camera before spectroscopic observations and the
  ability to extract spectra from up-the-ramp observations with the HPF
  infrared detector enable us to perform time-series analysis of part of
  the flare and provide coarse constraints on the energy and frequency
  of such flares. We compare this flare with historical observations of
  flares around vB 10 and other ultracool M dwarfs and attempt to place
  limits on flare-induced atmospheric mass loss for hypothetical planets
  around vB 10.

Title: Gaia 20eae: A Newly Discovered Episodically Accreting
    Young Star
Authors: Ghosh, Arpan; Sharma, Saurabh; Ninan, Joe P.; Ojha, Devendra
   K.; Bhatt, Bhuwan C.; Kanodia, Shubham; Mahadevan, Suvrath; Stefansson,
   Gudmundur; Yadav, R. K.; Gour, A. S.; Pandey, Rakesh; Sinha, Tirthendu;
   Panwar, Neelam; Wisniewski, John P.; Cañas, Caleb I.; Lin, Andrea
   S. J.; Roy, Arpita; Hearty, Fred; Ramsey, Lawrence; Robertson, Paul;
   Schwab, Christian
Bibcode: 2022ApJ...926...68G
Altcode: 2021arXiv211201717G
  The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae
  when its light curve showed a ~4.25 magnitude outburst. We present
  multiwavelength photometric and spectroscopic follow-up observations of
  this source since 2020 August and identify it as the newest member of
  the FUor/EXor family of sources. We find that the present brightening of
  Gaia 20eae is not due to the dust-clearing event but due to an intrinsic
  change in the spectral energy distribution. The light curve of Gaia
  20eae shows a transition stage during which most of its brightness
  (~3.4 mag) has occurred on a short timescale of 34 days with a rise
  rate of 3 mag/month. Gaia 20eae has now started to decay at a rate
  of 0.3 mag/month. We have detected a strong P Cygni profile in Hα,
  which indicates the presence of winds originating from regions close to
  the accretion. We find signatures of very strong and turbulent outflow
  and accretion in Gaia 20eae during this outburst phase. We have also
  detected a redshifted absorption component in all of the Ca II IR
  triplet lines consistent with a signature of hot infalling gas in
  the magnetospheric accretion funnel. This enables us to constrain the
  viewing angle with respect to the accretion funnel. Our investigation of
  Gaia 20eae points toward magnetospheric accretion being the phenomenon
  for the current outburst.

Title: A Hot Mars-sized Exoplanet Transiting an M Dwarf
Authors: Cañas, Caleb I.; Mahadevan, Suvrath; Cochran, William D.;
   Bender, Chad F.; Feigelson, Eric D.; Harman, C. E.; Kopparapu, Ravi
   Kumar; Caceres, Gabriel A.; Diddams, Scott A.; Endl, Michael; Ford,
   Eric B.; Halverson, Samuel; Hearty, Fred; Jones, Sinclaire; Kanodia,
   Shubham; Lin, Andrea S. J.; Metcalf, Andrew J.; Monson, Andrew; Ninan,
   Joe P.; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Schwab,
   Christian; Stefánsson, Guđmundur
Bibcode: 2022AJ....163....3C
Altcode: 2021arXiv211203958C
  We validate the planetary nature of an ultra-short-period planet
  orbiting the M dwarf KOI-4777. We use a combination of space-based
  photometry from Kepler, high-precision, near-infrared Doppler
  spectroscopy from the Habitable-zone Planet Finder, and adaptive
  optics imaging to characterize this system. KOI-4777.01 is a Mars-sized
  exoplanet (R <SUB> p </SUB> = 0.51 ± 0.03R <SUB>⊕</SUB>) orbiting the
  host star every 0.412 days (~9.9 hr). This is the smallest validated
  ultra-short period planet known and we see no evidence for additional
  massive companions using our HPF RVs. We constrain the upper 3σ mass
  to M <SUB> p </SUB> &lt; 0.34 M <SUB>⊕</SUB> by assuming the planet
  is less dense than iron. Obtaining a mass measurement for KOI-4777.01
  is beyond current instrumental capabilities.

Title: The HETDEX Instrumentation: Hobby-Eberly Telescope Wide-field
    Upgrade and VIRUS
Authors: Hill, Gary J.; Lee, Hanshin; MacQueen, Phillip J.; Kelz,
   Andreas; Drory, Niv; Vattiat, Brian L.; Good, John M.; Ramsey,
   Jason; Kriel, Herman; Peterson, Trent; DePoy, D. L.; Gebhardt,
   Karl; Marshall, J. L.; Tuttle, Sarah E.; Bauer, Svend M.; Chonis,
   Taylor S.; Fabricius, Maximilian H.; Froning, Cynthia; Häuser,
   Marco; Indahl, Briana L.; Jahn, Thomas; Landriau, Martin; Leck, Ron;
   Montesano, Francesco; Prochaska, Travis; Snigula, Jan M.; Zeimann,
   Greg; Bryant, Randy; Damm, George; Fowler, J. R.; Janowiecki, Steven;
   Martin, Jerry; Mrozinski, Emily; Odewahn, Stephen; Rostopchin, Sergey;
   Shetrone, Matthew; Spencer, Renny; Mentuch Cooper, Erin; Armandroff,
   Taft; Bender, Ralf; Dalton, Gavin; Hopp, Ulrich; Komatsu, Eiichiro;
   Nicklas, Harald; Ramsey, Lawrence W.; Roth, Martin M.; Schneider,
   Donald P.; Sneden, Chris; Steinmetz, Matthias
Bibcode: 2021AJ....162..298H
Altcode: 2021arXiv211003843H
  The Hobby-Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is
  undertaking a blind wide-field low-resolution spectroscopic survey
  of 540 deg<SUP>2</SUP> of sky to identify and derive redshifts for a
  million Lyα-emitting galaxies in the redshift range 1.9 &lt; z &lt;
  3.5. The ultimate goal is to measure the expansion rate of the universe
  at this epoch, to sharply constrain cosmological parameters and thus
  the nature of dark energy. A major multiyear Wide-Field Upgrade (WFU)
  of the HET was completed in 2016 that substantially increased the
  field of view to 22' diameter and the pupil to 10 m, by replacing the
  optical corrector, tracker, and Prime Focus Instrument Package and by
  developing a new telescope control system. The new, wide-field HET
  now feeds the Visible Integral-field Replicable Unit Spectrograph
  (VIRUS), a new low-resolution integral-field spectrograph (LRS2),
  and the Habitable Zone Planet Finder, a precision near-infrared radial
  velocity spectrograph. VIRUS consists of 156 identical spectrographs fed
  by almost 35,000 fibers in 78 integral-field units arrayed at the focus
  of the upgraded HET. VIRUS operates in a bandpass of 3500-5500 Å with
  resolving power R ≃ 800. VIRUS is the first example of large-scale
  replication applied to instrumentation in optical astronomy to achieve
  spectroscopic surveys of very large areas of sky. This paper presents
  technical details of the HET WFU and VIRUS, as flowed down from the
  HETDEX science requirements, along with experience from commissioning
  this major telescope upgrade and the innovative instrumentation suite
  for HETDEX.

Title: VizieR Online Data Catalog: Radial velocity follow up of
    Barnard's star with HPF (Lubin+, 2021)
Authors: Lubin, J.; Robertson, P.; Stefansson, G.; Ninan, J.;
   Mahadevan, S.; Endl, M.; Ford, E.; Wright, J. T.; Beard, C.; Bender,
   C.; Cochran, W. D.; Diddams, S. A.; Fredrick, C.; Halverson, S.;
   Kanodia, S.; Metcalf, A. J.; Ramsey, L.; Roy, A.; Schwab, C.;
   Terrien, R.
Bibcode: 2021yCat..51620061L
Altcode:
  Habitable Zone Planet Finder (HPF) is a high-resolution (R~55000)
  NIR spectrograph on the 10m Hobby-Eberly Telescope (HET), covering the
  Doppler-information-rich z, Y, and J bands from 810 to 1280nm. HPF has
  an NIR laser-frequency comb (LFC) calibrator, which has been shown to
  enable ~20cm/s calibration precision in 10minute bins and 1.53m/s RV
  precision on-sky on Barnard's star over an 3 month baseline. In this
  paper, we extend this baseline to 856 days. <P />(1 data file).

Title: A Search for Planetary Metastable Helium Absorption in the
    V1298 Tau System
Authors: Vissapragada, Shreyas; Stefánsson, Gudmundur; Greklek-McKeon,
   Michael; Oklopčić, Antonija; Knutson, Heather A.; Ninan, Joe P.;
   Mahadevan, Suvrath; Cañas, Caleb I.; Chachan, Yayaati; Cochran,
   William D.; Collins, Karen A.; Dai, Fei; David, Trevor J.; Halverson,
   Samuel; Hawley, Suzanne L.; Hebb, Leslie; Kanodia, Shubham; Kowalski,
   Adam F.; Livingston, John H.; Maney, Marissa; Metcalf, Andrew J.;
   Morley, Caroline; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita;
   Spake, Jessica; Schwab, Christian; Terrien, Ryan C.; Tinyanont,
   Samaporn; Vasisht, Gautam; Wisniewski, John
Bibcode: 2021AJ....162..222V
Altcode: 2021arXiv210805358V
  Early in their lives, planets endure extreme amounts of ionizing
  radiation from their host stars. For planets with primordial
  hydrogen and helium-rich envelopes, this can lead to substantial
  mass loss. Direct observations of atmospheric escape in young
  planetary systems can help elucidate this critical stage of planetary
  evolution. In this work, we search for metastable helium absorption-a
  tracer of tenuous gas in escaping atmospheres-during transits of three
  planets orbiting the young solar analog V1298 Tau. We characterize
  the stellar helium line using HET/HPF, and find that it evolves
  substantially on timescales of days to months. The line is stable
  on hour-long timescales except for one set of spectra taken during
  the decay phase of a stellar flare, where absoprtion increased with
  time. Utilizing a beam-shaping diffuser and a narrowband filter
  centered on the helium feature, we observe four transits with
  Palomar/WIRC: two partial transits of planet d (P = 12.4 days), one
  partial transit of planet b (P = 24.1 days), and one full transit of
  planet c (P = 8.2 days). We do not detect the transit of planet c,
  and we find no evidence of excess absorption for planet b, with ΔR
  <SUB>b</SUB>/R <SUB>⋆</SUB> &lt; 0.019 in our bandpass. We find
  a tentative absorption signal for planet d with ΔR <SUB>d</SUB>/R
  <SUB>⋆</SUB> = 0.0205 ± 0.054, but the best-fit model requires a
  substantial (-100 ± 14 minutes) transit-timing offset on a two-month
  timescale. Nevertheless, our data suggest that V1298 Tau d may have
  a high present-day mass-loss rate, making it a priority target for
  follow-up observations.

Title: VizieR Online Data Catalog: Radial velocities of TOI-1728
    with HPF (Kanodia+, 2020)
Authors: Kanodia, S.; Canas, C. I.; Stefansson, G.; Ninan, J. P.;
   Hebb, L.; Lin, A. S. J.; Baran, H.; Maney, M.; Terrien, R. C.;
   Mahadevan, S.; Cochran, W. D.; Endl, M.; Dong, J.; Bender, C. F.;
   Diddams, S. A.; Ford, E. B.; Fredrick, C.; Halverson, S.; Hearty,
   F.; Metcalf, A. J.; Monson, A.; Ramsey, L. W.; Robertson, P.; Roy,
   A.; Schwab, C.; Wright, J. T.
Bibcode: 2021yCat..18990029K
Altcode:
  TOI-1728 was observed by Transiting Exoplanet Survey Satellite
  (TESS) in Sector 20 from 2019 December 24 to 2020 January 19 at
  two-minute cadence. <P />We observed a transit of TOI-1728b on the
  night of 2020 February 22 using the Richard S. Perkin telescope on
  the campus of Hobart and William Smith Colleges (Geneva, New York,
  United States). The 0.43m (17") f/6.8 Planewave Corrected Dall-Kirkham
  (CDK) telescope rests on a Paramount equatorial mount with an SBIG8300M
  camera mounted at Cassegrain focus. The camera detector has an array
  of 3326x2504, 5.4μm pixels resulting in a ~21x16' field of view. We
  obtained a series of 92 consecutive images over 5hr centered on the
  target in 1x1 binning mode in the Sloan r' filter. <P />We observed a
  transit of TOI-1728b on the night of 2020 February 22 using the 0.6m
  telescope located on the roof of the Penn State Davey Laboratory
  (University Park, Pennsylvania, United States). The telescope was
  installed in 2014 and has an Apogee/Andor Aspen CG42 camera, using a
  CCD42-10 2048x2048 pixel chip from e2v with 13.5micron pixels. This
  results in a plate scale of ~0.77 per pixel and a field of view of
  24'x24'. The observations were made with the Johnson I filter and an
  engineered diffuser, with an exposure time of 45s. <P />We observed
  TOI-1728 using Habitable Planet Finder (HPF), a high-resolution
  (R~55000), NIR (8080-12780Å) precision RVel spectrograph located at
  the 10meter Hobby-Eberly Telescope (HET) in Texas. <P />(2 data files).

Title: TOI-532b: The Habitable-zone Planet Finder confirms a Large
    Super Neptune in the Neptune Desert orbiting a metal-rich M-dwarf host
Authors: Kanodia, Shubham; Stefansson, Gudmundur; Cañas, Caleb I.;
   Maney, Marissa; Lin, Andrea S. J.; Ninan, Joe P.; Jones, Sinclaire;
   Monson, Andrew; Parker, Brock A.; Kobulnicky, Henry A.; Rothenberg,
   Jason; Beard, Corey; Lubin, Jack; Robertson, Paul; Gupta, Arvind F.;
   Mahadevan, Suvrath; Cochran, William D.; Bender, Chad F.; Diddams,
   Scott A.; Fredrick, Connor; Halverson, Samuel; Hawley, Suzanne;
   Hearty, Fred; Hebb, Leslie; Kopparapu, Ravi; Metcalf, Andrew J.;
   Ramsey, Lawrence W.; Roy, Arpita; Schwab, Christian; Schutte, Maria;
   Terrien, Ryan C.; Wisniewski, John; Wright, Jason T.
Bibcode: 2021AJ....162..135K
Altcode: 2021arXiv210713670K
  We confirm the planetary nature of TOI-532b, using a combination of
  precise near-infrared radial velocities with the Habitable-zone Planet
  Finder, Transiting Exoplanet Survey Satellite (TESS) light curves,
  ground-based photometric follow up, and high-contrast imaging. TOI-532
  is a faint (J ~ 11.5) metal-rich M dwarf with T<SUB>eff</SUB> = 3957 ±
  69 K and [Fe/H] = 0.38 ± 0.04; it hosts a transiting gaseous planet
  with a period of ~2.3 days. Joint fitting of the radial velocities
  with the TESS and ground-based transits reveal a planet with radius
  of 5.82 ± 0.19 R<SUB>⊕</SUB>, and a mass of ${61.5}_{-9.3}^{+9.7}$
  M<SUB>⊕</SUB>. TOI-532b is the largest and most massive super Neptune
  detected around an M dwarf with both mass and radius measurements,
  and it bridges the gap between the Neptune-sized planets and the
  heavier Jovian planets known to orbit M dwarfs. It also follows the
  previously noted trend between gas giants and host-star metallicity for
  M-dwarf planets. In addition, it is situated at the edge of the Neptune
  desert in the Radius-Insolation plane, helping place constraints on
  the mechanisms responsible for sculpting this region of planetary
  parameter space.

Title: The Habitable-zone Planet Finder Detects a Terrestrial-mass
Planet Candidate Closely Orbiting Gliese 1151: The Likely Source of
    Coherent Low-frequency Radio Emission from an Inactive Star
Authors: Mahadevan, Suvrath; Stefánsson, Gudmundur; Robertson, Paul;
   Terrien, Ryan C.; Ninan, Joe P.; Holcomb, Rae J.; Halverson, Samuel;
   Cochran, William D.; Kanodia, Shubham; Ramsey, Lawrence W.; Wolszczan,
   Alexander; Endl, Michael; Bender, Chad F.; Diddams, Scott A.; Fredrick,
   Connor; Hearty, Fred; Monson, Andrew; Metcalf, Andrew J.; Roy, Arpita;
   Schwab, Christian
Bibcode: 2021ApJ...919L...9M
Altcode: 2021arXiv210202233M
  The coherent low-frequency radio emission detected by LOFAR from
  Gliese 1151, a quiescent M4.5 dwarf star, has radio emission properties
  consistent with theoretical expectations of star-planet interactions for
  an Earth-sized planet on a 1- to 5-day orbit. New near-infrared radial
  velocities from the Habitable-zone Planet Finder (HPF) spectrometer on
  the 10 m Hobby-Eberly Telescope at McDonald Observatory, combined with
  previous velocities from HARPS-N, reveal a periodic Doppler signature
  consistent with an $m\sin i=2.5\pm 0.5{M}_{\oplus }$ exoplanet on a
  2.02-day orbit. Precise photometry from the Transiting Exoplanet Survey
  Satellite (TESS) shows no flares or activity signature, consistent with
  a quiescent M dwarf. While no planetary transit is detected in the TESS
  data, a weak photometric modulation is detectable in the photometry
  at a ~2-day period. This independent detection of a candidate planet
  signal with the Doppler radial velocity technique adds further weight
  to the claim of the first detection of star-exoplanet interactions at
  radio wavelengths and helps validate this emerging technique for the
  detection of exoplanets.

Title: Stellar Activity Manifesting at a One-year Alias Explains
    Barnard b as a False Positive
Authors: Lubin, Jack; Robertson, Paul; Stefansson, Gudmundur; Ninan,
   Joe; Mahadevan, Suvrath; Endl, Michael; Ford, Eric; Wright, Jason T.;
   Beard, Corey; Bender, Chad; Cochran, William D.; Diddams, Scott A.;
   Fredrick, Connor; Halverson, Samuel; Kanodia, Shubham; Metcalf, Andrew
   J.; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian; Terrien, Ryan
Bibcode: 2021AJ....162...61L
Altcode:
  Barnard's star is among the most studied stars given its proximity
  to the Sun. It is often considered the radial velocity (RV) standard
  for fully convective stars due to its RV stability and equatorial
  decl. Recently, an $M\sin i=3.3{M}_{\oplus }$ super-Earth planet
  candidate with a 233 day orbital period was announced by Ribas et
  al. New observations from the near-infrared Habitable-zone Planet Finder
  (HPF) Doppler spectrometer do not show this planetary signal. We ran a
  suite of experiments on both the original data and a combined original +
  HPF data set. These experiments include model comparisons, periodogram
  analyses, and sampling sensitivity, all of which show the signal at
  the proposed period of 233 days is transitory in nature. The power in
  the signal is largely contained within 211 RVs that were taken within
  a 1000 day span of observing. Our preferred model of the system is
  one that features stellar activity without a planet. We propose that
  the candidate planetary signal is an alias of the 145 day rotation
  period. This result highlights the challenge of analyzing long-term,
  quasi-periodic activity signals over multiyear and multi-instrument
  observing campaigns.

Title: Stellar Activity Manifesting at a One Year Alias Explains
    Barnard b as a False Positive
Authors: Lubin, Jack; Robertson, Paul; Stefansson, Gudmundur; Ninan,
   Joe; Mahadevan, Suvrath; Endl, Michael; Ford, Eric; Wright, Jason T.;
   Beard, Corey; Bender, Chad; Cochran, William D.; Diddams, Scott A.;
   Fredrick, Connor; Halverson, Samuel; Kanodia, Shubham; Metcalf, Andrew
   J.; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian; Terrien, Ryan
Bibcode: 2021arXiv210507005L
Altcode:
  Barnard's star is among the most studied stars given its proximity to
  the Sun. It is often considered $the$ Radial Velocity (RV) standard
  for fully convective stars due to its RV stability and equatorial
  declination. Recently, an $M \sin i = 3.3 M_{\oplus}$ super-Earth
  planet candidate with a 233 day orbital period was announced by Ribas
  et al. (2018). New observations from the near-infrared Habitable-zone
  Planet Finder (HPF) Doppler spectrometer do not show this planetary
  signal. We ran a suite of experiments on both the original data and
  a combined original + HPF data set. These experiments include model
  comparisons, periodogram analyses, and sampling sensitivity, all of
  which show the signal at the proposed period of 233 days is transitory
  in nature. The power in the signal is largely contained within 211
  RVs that were taken within a 1000 day span of observing. Our preferred
  model of the system is one which features stellar activity without a
  planet. We propose that the candidate planetary signal is an alias of
  the 145 day rotation period. This result highlights the challenge of
  analyzing long-term, quasi-periodic activity signals over multi-year
  and multi-instrument observing campaigns.

Title: A Harsh Test of Far-field Scrambling with the Habitable-zone
    Planet Finder and the Hobby-Eberly Telescope
Authors: Kanodia, Shubham; Halverson, Samuel; Ninan, Joe P.; Mahadevan,
   Suvrath; Stefansson, Gudmundur; Roy, Arpita; Ramsey, Lawrence W.;
   Bender, Chad F.; Janowiecki, Steven; Cochran, William D.; Diddams,
   Scott A.; Drory, Niv; Endl, Michael; Ford, Eric B.; Hearty, Fred;
   Metcalf, Andrew J.; Monson, Andrew; Robertson, Paul; Schwab, Christian;
   Terrien, Ryan C.; Wright, Jason T.
Bibcode: 2021ApJ...912...15K
Altcode: 2021arXiv210305148K
  The Habitable-zone Planet Finder (HPF) is a fiber-fed precise radial
  velocity (RV) spectrograph at the 10 m Hobby-Eberly Telescope (HET). Due
  to its fixed-altitude design, the HET pupil changes appreciably
  across a track, leading to significant changes of the fiber far-field
  illumination. HPF's fiber scrambler is designed to suppress the impact
  of these illumination changes on the RVs—but the residual impact on
  the RV measurements has yet to be probed on-sky. We use GJ 411, a bright
  early type (M2) M dwarf to probe the effects of far-field input trends
  due to these pupil variations on HPF RVs. These large changes (∼2x)
  in the pupil area and centroid present a harsh test of HPF's far-field
  scrambling. Our results show that the RVs are effectively decoupled
  from these extreme far-field input changes due to pupil centroid
  offsets, attesting to the effectiveness of the scrambler design. This
  experiment allows us to test the impact of these changes with large
  pupil variation on-sky, something we would not easily be able to do
  at a conventional optical telescope. While the pupil and illumination
  changes expected at these other telescopes are small, scaling from
  our results enables us to estimate and bound these effects, and show
  that they are controllable even for the new and next generation of
  RV instruments in their quest to beat down instrumental noise sources
  toward the goal of a few $\,\mathrm{cm}\,{{\rm{s}}}^{-1}$ .

Title: VizieR Online Data Catalog: Chemical composition of 15 red
    giant stars with HPF (Sneden+, 2021)
Authors: Sneden, C.; Afsar, M.; Bozkurt, Z.; Topcu, G. B.; Ozdemir,
   S.; Zeimann, G. R.; Froning, C. S.; Mahadevan, S.; Ninan, J. P.;
   Bender, C. F.; Terrien, R.; Ramsey, L. W.; Lind, K.; Mace, G. N.;
   Kaplan, K. F.; Kim, H.; Hawkins, K.; Bowler, B. P.
Bibcode: 2021yCat..51610128S
Altcode:
  The red giants investigated in this Habitable Planet Finder (HPF)
  spectroscopic study have been selected from our previous studies. See
  those papers for detailed descriptions of the optical observations of
  our program stars. HPF is a high-resolution (R~55000) near-infrared (zyJ
  photometric bands, 8100-12800Å) spectrograph on the 10m Hobby-Eberly
  Telescope (HET) at McDonald Observatory. <P />(4 data files).

Title: Exploring flares around the ultracool M dwarf VB-10 with high
    resolution infrared spectroscopy
Authors: Kanodia, Shubham; Ramsey, Lawrence; Ninan, P. Joe; Mahadevan,
   Suvrath
Bibcode: 2021csss.confE.286K
Altcode:
  Flare activity in late M stars remains an interesting topic since there
  is as yet no well tested model of how these convective stars generate
  the magnetic field that underlie activity such as flares, and the rate
  and strengths of the flare can impact the evolution of the atmospheres
  of planets orbiting them We present observations of two flares observed
  on the M8 star VB10 with the Habitable zone Planet Finder (HPF) on
  the Hobby Eberly Telescope. HPF is designed to be very stable for
  precision radial velocities but its NIR coverage (810-1280 nm) and
  queue scheduled operations allow us to obtain multiple observations
  to analyze the properties of the flares. A combination of the 10 m
  telescope aperture with the nondestructive read readout with our H2RG
  enables us to obtain a time resolution of ~ minutes on this late type
  M dwarf, which helps us resolve the evolution of the flare. We present
  our analysis of the Ca II infrared triple lines as well as Pa $\gamma$
  and $\delta$ to place constraints on the time behavior and physical
  conditions of the emitting material.

Title: A Terrestrial-mass Planet Orbiting GJ 1151: The Possible
    Source of Coherent Low-frequency Radio Emission from an Inactive Star
Authors: Stefansson, Gudmundur; Mahadevan, Suvrath; Robertson, Paul;
   Terrien, Ryan; Ninan, Joe; Holcomb, Rae; Halverson, Samuel; Cochran,
   William; Kanodia, Shubham; Ramsey, Lawrence; Wolszczan, Alexander;
   Endl, Michael; Bender, Chad; Diddams, Scott; Frederick, Connor;
   Hearty, Frederick; Monson, Andrew; Metcalf, Andrew; Roy, Arpita;
   Schwab, Christian
Bibcode: 2021csss.confE.107S
Altcode:
  The coherent low-frequency radio emission detected by LOFAR from
  the quiescent M4.5 dwarf star GJ 1151 is consistent with theoretical
  expectations of star-planet interactions for an Earth-sized planet on
  a 1-5 day orbit. Using precise near-infrared radial velocities (RVs)
  with the Habitable-zone Planet Finder (HPF) on the 10m Hobby-Eberly
  Telescope at McDonald Observatory along with literature RVs from
  HARPS-N, we reveal a periodic Doppler signature consistent with a
  2.5 Earth mass planet in a 2.02-day orbit. Precise photometry from the
  Transiting Exoplanet Survey Satellite (TESS) shows no flares or activity
  signature, consistent with a quiescent M dwarf. While no planetary
  transit is detected in the TESS data, a weak photometric modulation
  is detectable in the photometry at a ~2 day period. This independent
  detection of a planet signal with the RV technique adds further
  weight to the claim to one of the first detection of star-exoplanet
  interactions at radio wavelengths, and helps validate this emerging
  technique for the detection of exoplanets.&lt;strong&gt; &lt;/strong&gt;

Title: Chemical Compositions of Red Giant Stars from Habitable Zone
    Planet Finder Spectroscopy
Authors: Sneden, Christopher; Afşar, Melike; Bozkurt, Zeynep; Topcu,
   Gamze Böcek; Özdemir, Sergen; Zeimann, Gregory R.; Froning, Cynthia
   S.; Mahadevan, Suvrath; Ninan, Joe P.; Bender, Chad F.; Terrien, Ryan;
   Ramsey, Lawrence W.; Lind, Karin; Mace, Gregory N.; Kaplan, Kyle F.;
   Kim, Hwihyun; Hawkins, Keith; Bowler, Brendan P.
Bibcode: 2021AJ....161..128S
Altcode: 2020arXiv201214742S
  We have used the Habitable Zone Planet Finder (HPF) to gather
  high-resolution, high signal-to-noise near-infrared spectra of 13
  field red horizontal branch (RHB) stars, one open cluster giant,
  and one very metal-poor halo red giant. The HPF spectra cover the
  0.81-1.28 μm wavelength range of the zyJ bands, partially filling
  the gap between the optical (0.4-1.0 μm) and infrared (1.5-2.4 μm)
  spectra already available for the program stars. We derive abundances of
  17 species from LTE-based computations involving equivalent widths and
  spectrum syntheses, and estimate abundance corrections for the species
  that are most affected by departures from LTE in RHB stars. Generally
  good agreement is found between HPF-based metallicities and abundance
  ratios and those from the optical and infrared spectral regions. Light
  element transitions dominate the HPF spectra of these red giants, and
  HPF data can be used to derive abundances from species with poor or no
  representation in optical spectra (e.g., C I, P I, S I, K I). Attention
  is drawn to the HPF abundances in two field solar-metallicity RHB stars
  of special interest: one with an extreme carbon isotope ratio, and one
  with a rare, very large lithium content. The latter star is unique in
  our sample in exhibiting very strong He I 10830 Å absorption. The
  abundances of the open cluster giant concur with those derived from
  other wavelength regions. Detections of C I and S I in HD 122563 are
  reported, yielding the lowest metallicity determination of [S/Fe]
  from more than one multiplet.

Title: VizieR Online Data Catalog: HPF RVs and TESS photometry of
    TOI-1266 (Stefansson+, 2020)
Authors: Stefansson, G.; Kopparapu, R.; Lin, A.; Mahadevan, S.; Canas,
   C. I.; Kanodia, S.; Ninan, J. P.; Cochran, W. D.; Endl, M.; Hebb,
   L.; Wisniewski, J.; Gupta, A.; Everett, M.; Bender, C. F.; Diddams,
   S. A.; Ford, E. B.; Fredrick, C.; Halverson, S.; Hearty, F.; Levi,
   E.; Maney, M.; Metcalf, A. J.; Monson, A.; Ramsey, L. W.; Robertson,
   P.; Roy, A.; Schwab, C.; Terrien, R. C.; Wright, J. T.
Bibcode: 2021yCat..51600259S
Altcode:
  We obtained high-resolution spectra of TOI-1266 with the Habitable
  Planet Finder (HPF) Spectrograph to place upper limits on the masses
  of both planets and obtain precise spectroscopic parameters of the
  host star. The HPF is a fiber-fed near-infrared (NIR) spectrograph on
  the 10m Hobby-Eberly Telescope (HET) at McDonald Observatory in Texas,
  covering the z, Y, and J bands from 810 to 1260nm at a resolution of
  R=55000. <P />The Telescope Encoder and Sky Sensor (TESS) observed
  TOI-1266 in 4 sectors: sector 14 (camera4; 2019 July 18--2019 August
  15), sector 15 (camera4; 2019 August 15--2019 September 11), sector 21
  (camera3; 2020 January 21--2020 February 18), and sector 22 (camera3;
  2020 February 18--2020 March 18). <P />(2 data files).

Title: A Mini-Neptune and a Radius Valley Planet Orbiting the
Nearby M2 Dwarf TOI-1266 in Its Venus Zone: Validation with the
    Habitable-zone Planet Finder
Authors: Stefánsson, Guðmundur; Kopparapu, Ravi; Lin, Andrea;
   Mahadevan, Suvrath; Cañas, Caleb I.; Kanodia, Shubham; Ninan, Joe P.;
   Cochran, William D.; Endl, Michael; Hebb, Leslie; Wisniewski, John;
   Gupta, Arvind; Everett, Mark; Bender, Chad F.; Diddams, Scott A.;
   Ford, Eric B.; Fredrick, Connor; Halverson, Samuel; Hearty, Fred;
   Levi, Eric; Maney, Marissa; Metcalf, Andrew J.; Monson, Andrew; Ramsey,
   Lawrence W.; Robertson, Paul; Roy, Arpita; Schwab, Christian; Terrien,
   Ryan C.; Wright, Jason T.
Bibcode: 2020AJ....160..259S
Altcode:
  We report on the validation of two planets orbiting the nearby (36
  pc) M2 dwarf TOI-1266 observed by the TESS mission. This system is
  one of a few M dwarf multiplanet systems with close-in planets where
  the inner planet is substantially larger than the outer planet. The
  inner planet is sub-Neptune-sized (R = 2.46 ± 0.08 R<SUB>⊕</SUB>)
  with an orbital period of 10.9 days, while the outer planet has a
  radius of ${1.67}_{-0.11}^{+0.09}$ R<SUB>⊕</SUB> and resides in
  the exoplanet radius valley—the transition region between rocky and
  gaseous planets. With an orbital period of 18.8 days, the outer planet
  receives an insolation flux of 2.4 times that of Earth, similar to the
  insolation of Venus. Using precision near-infrared radial velocities
  with the Habitable-zone Planet Finder Spectrograph, we place upper mass
  limits of 15.9 and 6.4 M<SUB>⊕</SUB> at 95% confidence for the inner
  and outer planet, respectively. A more precise mass constraint of both
  planets, achievable with current radial velocity instruments given the
  host star brightness (V = 12.9, J = 9.7), will yield further insights
  into the dominant processes sculpting the exoplanet radius valley.

Title: Ghosts of NEID's past
Authors: Kanodia, Shubham; Ninan, Joe P.; Monson, Andrew J.; Mahadevan,
   Suvrath; Nitroy, Colin; Schwab, Christian; Halverson, Samuel; Bender,
   Chad F.; Terrien, Ryan; Hearty, Frederick R.; Lubar, Emily; McElwain,
   Michael W.; Ramsey, Lawrence W.; Robertson, Paul M.; Roy, Arpita;
   Stefansson, Gudmundur; Stevens, Daniel J.
Bibcode: 2020SPIE11447E..40K
Altcode: 2020arXiv201200182K
  The NEID spectrograph is a R ~ 120,000 resolution fiber-fed and highly
  stabilized spectrograph for extreme radial velocity (RV) precision. It
  is being commissioned at the 3.5 m WIYN telescope in Kitt Peak National
  Observatory with a desired instrumental precision of better than 30 cm
  s<SUP>-1</SUP>. NEID's bandpass of 380 - 930 nm enables the simultaneous
  wavelength coverage of activity indicators from the Ca HK lines in the
  blue to the Ca IR triplet in the IR. In this paper we will present
  our efforts to characterize and mitigate optical ghosts in the NEID
  spectrograph during assembly, integration and testing, and highlight
  several of the dominant optical element contributors such as the
  cross dispersion prism and input optics. We shall present simulations
  of the 2-D spectrum and discuss the predicted ghost features on the
  focal plane, and how they may impact the RV performance for NEID. We
  also present the mitigation strategy adopted for each ghost which
  may be applied to future instrument designs. This work will enable
  other instrument builders to potentially avoid some of these issues,
  as well as outline mitigation strategies.

Title: VizieR Online Data Catalog: Photometry and RVs of K2-25b with
    HPF (Stefansson+, 2020)
Authors: Stefansson, G.; Mahadevan, S.; Maney, M.; Ninan, J. P.;
   Robertson, P.; Rajagopal, J.; Haase, F.; Allen, L.; Ford, E. B.;
   Winn, J.; Wolfgang, A.; Dawson, R. I.; Wisniewski, J.; Bender, C. F.;
   Canas, C.; Cochran, W.; Diddams, S. A.; Fredrick, C.; Halverson, S.;
   Hearty, F.; Hebb, L.; Kanodia, S.; Levi, E.; Metcalf, A. J.; Monson,
   A.; Ramsey, L.; Roy, A.; Schwab, C.; Terrien, R.; Wright, J. T.
Bibcode: 2020yCat..51600192S
Altcode:
  We obtained five transits of K2-25b using the Astrophysical Research
  Consortium Telescope Imaging Camera (ARCTIC) imager on the 3.5m
  Astrophysical Research Consortium (ARC) 3.5m Telescope at Apache Point
  Observatory (APO) on the nights of UT 2017 September 17; 2019 January
  4, 18, and 25; and 2019 February 1. All of the transit observations
  were performed with the Engineered Diffuser available on ARCTIC, which
  we designed specifically to enable very high precision photometric
  observations. We used the Sloan Digital Sky Survey (SDSS) i' filter,
  except on the night of 2019 January 18, when we used the SDSS z' filter
  without the diffuser to minimize background Moon contamination. <P
  />We observed four transits of K2-25b using the Half-Degree Imager
  (HDI) at the WIYN 0.9m telescope at Kitt Peak National Observatory
  on the nights of UT 2018 February 7 and 21 and 2018 December 14 and
  21. <P />We obtained precision Near Infra Red (NIR) Radial Velocities
  (RVs) of K2-25 with the Habitable Zone Planet Finder (HPF) with the
  twofold goal to constrain the mass of K2-25b and the obliquity of
  the host star. The HPF is a high-resolution (R~55000) NIR fiber-fed
  spectrograph on the 10m Hobby-Eberly Telescope (HET) at McDonald
  Observatory in Texas. <P />(3 data files).

Title: The Habitable Zone Planet Finder Reveals a High Mass and Low
    Obliquity for the Young Neptune K2-25b
Authors: Stefansson, Gudmundur; Mahadevan, Suvrath; Maney, Marissa;
   Ninan, Joe P.; Robertson, Paul; Rajagopal, Jayadev; Haase, Flynn;
   Allen, Lori; Ford, Eric B.; Winn, Joshua; Wolfgang, Angie; Dawson,
   Rebekah I.; Wisniewski, John; Bender, Chad F.; Cañas, Caleb; Cochran,
   William; Diddams, Scott A.; Fredrick, Connor; Halverson, Samuel;
   Hearty, Fred; Hebb, Leslie; Kanodia, Shubham; Levi, Eric; Metcalf,
   Andrew J.; Monson, Andrew; Ramsey, Lawrence; Roy, Arpita; Schwab,
   Christian; Terrien, Ryan; Wright, Jason T.
Bibcode: 2020AJ....160..192S
Altcode: 2020arXiv200712766S
  Using radial velocity data from the Habitable Zone Planet Finder, we
  have measured the mass of the Neptune-sized planet K2-25b, as well as
  the obliquity of its M4.5 dwarf host star in the 600-800 Myr Hyades
  cluster. This is one of the youngest planetary systems for which
  both of these quantities have been measured and one of the very few
  M dwarfs with a measured obliquity. Based on a joint analysis of the
  radial velocity data, time-series photometry from the K2 mission, and
  new transit light curves obtained with diffuser-assisted photometry,
  the planet's radius and mass are 3.44 ± 0.12 R<SUB>⊕</SUB> and
  ${24.5}_{-5.2}^{+5.7}{M}_{\oplus }$ . These properties are compatible
  with a rocky core enshrouded by a thin hydrogen-helium atmosphere (5%
  by mass). We measure an orbital eccentricity of e = 0.43 ± 0.05. The
  sky-projected stellar obliquity is λ = 3° ± 16°, compatible with
  spin-orbit alignment, in contrast to other "hot Neptunes" that have
  been studied around older stars.

Title: A Warm Jupiter Transiting an M Dwarf: A TESS Single-transit
    Event Confirmed with the Habitable-zone Planet Finder
Authors: Cañas, Caleb I.; Stefansson, Gudmundur; Kanodia, Shubham;
   Mahadevan, Suvrath; Cochran, William D.; Endl, Michael; Robertson,
   Paul; Bender, Chad F.; Ninan, Joe P.; Beard, Corey; Lubin, Jack; Gupta,
   Arvind F.; Everett, Mark E.; Monson, Andrew; Wilson, Robert F.; Lewis,
   Hannah M.; Brewer, Mary; Majewski, Steven R.; Hebb, Leslie; Dawson,
   Rebekah I.; Diddams, Scott A.; Ford, Eric B.; Fredrick, Connor;
   Halverson, Samuel; Hearty, Fred; Lin, Andrea S. J.; Metcalf, Andrew
   J.; Rajagopal, Jayadev; Ramsey, Lawrence W.; Roy, Arpita; Schwab,
   Christian; Terrien, Ryan C.; Wright, Jason T.
Bibcode: 2020AJ....160..147C
Altcode: 2020arXiv200707098C
  We confirm the planetary nature of a warm Jupiter transiting the early
  M dwarf TOI-1899 using a combination of available TESS photometry;
  high-precision, near-infrared spectroscopy with the Habitable-zone
  Planet Finder; and speckle and adaptive optics imaging. The data
  reveal a transiting companion on an ∼29 day orbit with a mass and
  radius of $0.66\pm 0.07\ {M}_{{\rm{J}}}$ and ${1.15}_{-0.05}^{+0.04}\
  {R}_{{\rm{J}}}$ , respectively. The star, TOI-1899, is the lowest-mass
  star known to host a transiting warm Jupiter, and we discuss the
  follow-up opportunities afforded by a warm ( ${T}_{\mathrm{eq}}\sim
  362$ K) gas giant orbiting an M0 star. Our observations reveal that
  TOI-1899.01 is a puffy warm Jupiter, and we suggest additional transit
  observations to both refine the orbit and constrain the true dilution
  observed in TESS.

Title: VizieR Online Data Catalog: Flux &amp; RVs of the dwarf G9-40
    with K2 &amp; HPF (Stefansson+, 2020)
Authors: Stefansson, G.; Canas, C.; Wisniewski, J.; Robertson, P.;
   Mahadevan, S.; Maney, M.; Kanodia, S.; Beard, C.; Bender, C. F.;
   Brunt, P.; Clemens, J. C.; Cochran, W.; Diddams, S. A.; Endl, M.; Ford,
   E. B.; Fredrick, C.; Halverson, S.; Hearty, F.; Hebb, L.; Huehnerhoff,
   J.; Jennings, J.; Kaplan, K.; Levi, E.; Lubar, E.; Metcalf, A. J.;
   Monson, A.; Morris, B.; Ninan, J. P.; Nitroy, C.; Ramsey, L.; Roy,
   A.; Schwab, C.; Sigurdsson, S.; Terrien, R.; Wright, J. T.
Bibcode: 2020yCat..51590100S
Altcode:
  G9-40 was observed by the Kepler spacecraft as part of Campaign 16
  of the K2 mission. It was proposed as a K2 Campaign 16 target by the
  following programs: GO16005<SUB>LC (PI: Crossfield), GO16009</SUB>LC
  (PI: Charbonneau), GO16052<SUB>LC (PI: Stello), and GO16083</SUB>LC
  (PI: Coughlin). The star was monitored in long cadence mode (30 minute
  cadence) for 80 days from 2017-December-7 to 2018-February-25. <P />We
  obtained four visits of G9-40 with the Habitable-zone Planet Finder
  (HPF) Spectrograph with the goal to measure its Radial Velocity (RV)
  variation as a function of time. HPF is a high-resolution (R~55000) NIR
  spectrograph recently commissioned on the 10m Hobby-Eberly Telescope
  (HET) in Texas covering the information-rich z, Y, and J bands from
  810 to 1280nm. <P />(2 data files).

Title: TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm
    Super-Neptune Orbiting an M-dwarf Host
Authors: Kanodia, Shubham; Cañas, Caleb I.; Stefansson, Gudmundur;
   Ninan, Joe P.; Hebb, Leslie; Lin, Andrea S. J.; Baran, Helen; Maney,
   Marissa; Terrien, Ryan C.; Mahadevan, Suvrath; Cochran, William D.;
   Endl, Michael; Dong, Jiayin; Bender, Chad F.; Diddams, Scott A.;
   Ford, Eric B.; Fredrick, Connor; Halverson, Samuel; Hearty, Fred;
   Metcalf, Andrew J.; Monson, Andrew; Ramsey, Lawrence W.; Robertson,
   Paul; Roy, Arpita; Schwab, Christian; Wright, Jason T.
Bibcode: 2020ApJ...899...29K
Altcode: 2020arXiv200614546K
  We confirm the planetary nature of TOI-1728b using a combination
  of ground-based photometry, near-infrared Doppler velocimetry and
  spectroscopy with the Habitable-zone Planet Finder. TOI-1728 is an
  old, inactive M0 star with T<SUB>eff</SUB> = ${3980}_{-32}^{+31}$ K,
  which hosts a transiting super-Neptune at an orbital period of ∼3.49
  days. Joint fitting of the radial velocities and TESS and ground-based
  transits yields a planetary radius of ${5.05}_{-0.17}^{+0.16}$
  R<SUB>⊕</SUB>, mass ${26.78}_{-5.13}^{+5.43}$ M<SUB>⊕</SUB>,
  and eccentricity ${0.057}_{-0.039}^{+0.054}$ . We estimate the
  stellar properties, and perform a search for He 10830 Šabsorption
  during the transit of this planet and claim a null detection with an
  upper limit of 1.1% with 90% confidence. A deeper level of He 10830
  Šabsorption has been detected in the planet atmosphere of GJ 3470b, a
  comparable gaseous planet. TOI-1728b is the largest super-Neptune—the
  intermediate subclass of planets between Neptune and the more massive
  gas-giant planets—discovered around an M dwarf. With its relatively
  large mass and radius, TOI-1728 represents a valuable data point in
  the M-dwarf exoplanet mass-radius diagram, bridging the gap between the
  lighter Neptune-sized planets and the heavier Jovian planets known to
  orbit M dwarfs. With a low bulk density of ${1.14}_{-0.24}^{+0.26}$
  g cm<SUP>-3</SUP>, and orbiting a bright host star (J ∼ 9.6, V
  ∼ 12.4), TOI-1728b is also a promising candidate for transmission
  spectroscopy both from the ground and from space, which can be used
  to constrain planet formation and evolutionary models.

Title: Persistent Starspot Signals on M Dwarfs: Multiwavelength
    Doppler Observations with the Habitable-zone Planet Finder and
    Keck/HIRES
Authors: Robertson, Paul; Stefansson, Gudmundur; Mahadevan, Suvrath;
   Endl, Michael; Cochran, William D.; Beard, Corey; Bender, Chad F.;
   Diddams, Scott A.; Duong, Nicholas; Ford, Eric B.; Fredrick, Connor;
   Halverson, Samuel; Hearty, Fred; Holcomb, Rae; Juan, Lydia; Kanodia,
   Shubham; Lubin, Jack; Metcalf, Andrew J.; Monson, Andrew; Ninan, Joe
   P.; Palafoutas, Jonathan; Ramsey, Lawrence W.; Roy, Arpita; Schwab,
   Christian; Terrien, Ryan C.; Wright, Jason T.
Bibcode: 2020ApJ...897..125R
Altcode: 2020arXiv200509657R
  Young, rapidly rotating M dwarfs exhibit prominent starspots,
  which create quasiperiodic signals in their photometric and
  Doppler spectroscopic measurements. The periodic Doppler signals
  can mimic radial velocity (RV) changes expected from orbiting
  exoplanets. Exoplanets can be distinguished from activity-induced
  false positives by the chromaticity and long-term incoherence of
  starspot signals, but these qualities are poorly constrained for fully
  convective M stars. Coherent photometric starspot signals on M dwarfs
  may persist for hundreds of rotations, and the wavelength dependence
  of starspot RV signals may not be consistent between stars due to
  differences in their magnetic fields and active regions. We obtained
  precise multiwavelength RVs of four rapidly rotating M dwarfs (AD Leo,
  G227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone
  Planet Finder and the optical Keck/HIRES spectrometer. Our RVs are
  complemented by photometry from Kepler, TESS, and the Las Cumbres
  Observatory network of telescopes. We found that all four stars
  exhibit large spot-induced Doppler signals at their rotation periods,
  and investigated the longevity and optical-to-NIR chromaticity for
  these signals. The phase curves remain coherent much longer than is
  typical for Sunlike stars. Their chromaticity varies, and one star (GJ
  3959) exhibits optical and NIR RV modulation consistent in both phase
  and amplitude. In general, though, we find that the NIR amplitudes
  are lower than their optical counterparts. We conclude that starspot
  modulation for rapidly rotating M stars frequently remains coherent for
  hundreds of stellar rotations and gives rise to Doppler signals that,
  due to this coherence, may be mistaken for exoplanets.

Title: A Mini-Neptune and a Venus-Zone Planet in the Radius
Valley Orbiting the Nearby M2-dwarf TOI-1266: Validation with the
    Habitable-zone Planet Finder
Authors: Stefansson, Gudmundur; Kopparapu, Ravi; Lin, Andrea;
   Mahadevan, Suvrath; Cañas, Caleb; Kanodia, Shubham; Ninan, Joe;
   Cochran, William; Endl, Michael; Hebb, Leslie; Wisniewski, John;
   Gupta, Arvind; Everett, Mark; Bender, Chad; Diddams, Scott; Ford, Eric;
   Fredrick, Connor; Halverson, Samuel; Hearty, Fred; Levi, Eric; Maney,
   Marissa; Metcalf, Andrew; Monson, Andrew; Ramsey, Lawrence; Robertson,
   Paul; Roy, Arpita; Schwab, Christian; Terrien, Ryan; Wright, Jason
Bibcode: 2020arXiv200611180S
Altcode:
  We report on the validation of two planets orbiting the nearby (36pc)
  M2 dwarf TOI-1266 observed by the TESS mission. The inner planet is
  sub-Neptune-sized ($R=2.46 \pm 0.08 R_\oplus$) with an orbital period
  of 10.9 days. The outer planet has a radius of $1.67_{-0.11}^{+0.09}
  R_\oplus$ and resides in the exoplanet Radius Valley---the transition
  region between rocky and gaseous planets. With an orbital period of
  18.8 days, the outer planet receives an insolation flux of 2.4 times
  that of Earth, similar to the insolation of Venus. Using precision
  near-infrared radial velocities with the Habitable-zone Planet
  Finder Spectrograph, we place upper mass limits of $15.9 M_\oplus$
  and $6.4 M_\oplus$ at 95% confidence for the inner and outer planet,
  respectively. A more precise mass constraint of planet c, achievable
  with current RV instruments given the host star brightness (V=12.9,
  J=9.7), will yield further insights into the dominant processes
  sculpting the exoplanet Radius Valley.

Title: Evidence for He I 10830 Å Absorption during the Transit of
    a Warm Neptune around the M-dwarf GJ 3470 with the Habitable-zone
    Planet Finder
Authors: Ninan, Joe P.; Stefansson, Gudmundur; Mahadevan, Suvrath;
   Bender, Chad; Robertson, Paul; Ramsey, Lawrence; Terrien, Ryan; Wright,
   Jason; Diddams, Scott A.; Kanodia, Shubham; Cochran, William; Endl,
   Michael; Ford, Eric B.; Fredrick, Connor; Halverson, Samuel; Hearty,
   Fred; Jennings, Jeff; Kaplan, Kyle; Lubar, Emily; Metcalf, Andrew J.;
   Monson, Andrew; Nitroy, Colin; Roy, Arpita; Schwab, Christian
Bibcode: 2020ApJ...894...97N
Altcode: 2019arXiv191002070N
  Understanding the dynamics and kinematics of outflowing atmospheres
  of hot and warm exoplanets is crucial to understanding the origins
  and evolutionary history of the exoplanets near the evaporation
  desert. Recently, ground-based measurements of the meta-stable helium
  atom's resonant absorption at 10830 Å has become a powerful probe
  of the base environment which is driving the outflow of exoplanet
  atmospheres. We report evidence for the He I 10830 Å in absorption
  (equivalent width ∼0.012 ± 0.002 Å) in the exosphere of a warm
  Neptune orbiting the M-dwarf GJ 3470, during three transits using the
  Habitable Zone Planet Finder near-infrared spectrograph. This marks the
  first reported evidence for He I 10830 Å atmospheric absorption for
  a planet orbiting an M-dwarf. Our detected absorption is broad and its
  blueshifted wing extends to -36 km s<SUP>-1</SUP>, the largest reported
  in the literature to date. We modeled the state of helium atoms in the
  exosphere of GJ3470b based on assumptions on the UV and X-ray flux of
  GJ 3470, and found our measurement of flux-weighted column density of
  meta-stable state helium $({N}_{\mathrm{He}{}_{3}^{2}{\rm{S}}}=2.4\times
  {10}^{10}\,{\mathrm{cm}}^{-2})$ , derived from our transit observations,
  to be consistent with the model, within its uncertainties. The
  methodology developed here will be useful to study and constrain the
  atmospheric outflow models of other exoplanets like GJ 3470b, which
  are near the edge of the evaporation desert.

Title: A Sub-Neptune-sized Planet Transiting the M2.5 Dwarf G 9-40:
    Validation with the Habitable-zone Planet Finder
Authors: Stefansson, Gudmundur; Cañas, Caleb; Wisniewski, John;
   Robertson, Paul; Mahadevan, Suvrath; Maney, Marissa; Kanodia, Shubham;
   Beard, Corey; Bender, Chad F.; Brunt, Peter; Clemens, J. Christopher;
   Cochran, William; Diddams, Scott A.; Endl, Michael; Ford, Eric B.;
   Fredrick, Connor; Halverson, Samuel; Hearty, Fred; Hebb, Leslie;
   Huehnerhoff, Joseph; Jennings, Jeff; Kaplan, Kyle; Levi, Eric; Lubar,
   Emily; Metcalf, Andrew J.; Monson, Andrew; Morris, Brett; Ninan, Joe
   P.; Nitroy, Colin; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian;
   Sigurdsson, Steinn; Terrien, Ryan; Wright, Jason T.
Bibcode: 2020AJ....159..100S
Altcode: 2019arXiv191200291S
  We validate the discovery of a 2-Earth-radii sub-Neptune-sized
  planet around the nearby high-proper-motion M2.5 dwarf G 9-40 (EPIC
  212048748), using high-precision, near-infrared (NIR) radial velocity
  (RV) observations with the Habitable-zone Planet Finder (HPF), precision
  diffuser-assisted ground-based photometry with a custom narrowband
  photometric filter, and adaptive optics imaging. At a distance of d
  = 27.9 $\,\mathrm{pc}$ , G 9-40b is the second-closest transiting
  planet discovered by K2 to date. The planet's large transit depth
  (∼3500 ppm), combined with the proximity and brightness of the host
  star at NIR wavelengths (J = 10, K = 9.2), makes G 9-40b one of the
  most favorable sub-Neptune-sized planets orbiting an M dwarf for
  transmission spectroscopy with James Webb Space Telescope, ARIEL,
  and the upcoming Extremely Large Telescopes. The star is relatively
  inactive with a rotation period of ∼29 days determined from the K2
  photometry. To estimate spectroscopic stellar parameters, we describe
  our implementation of an empirical spectral-matching algorithm
  using the high-resolution NIR HPF spectra. Using this algorithm,
  we obtain an effective temperature of ${T}_{\mathrm{eff}}=3404\pm
  73\,{\rm{K}}$ and metallicity of $[\mathrm{Fe}/{\rm{H}}]=-0.08\pm 0.13$
  . Our RVs, when coupled with the orbital parameters derived from the
  transit photometry, exclude planet masses above 11.7M<SUB>⊕</SUB>
  with 99.7% confidence assuming a circular orbit. From its radius,
  we predict a mass of $M={5.0}_{-1.9}^{+3.8}{M}_{\oplus }$ and an RV
  semiamplitude of $K={4.1}_{-1.6}^{+3.1}\,{\rm{m}}\ {{\rm{s}}}^{-1}$ ,
  making its mass measurable with current RV facilities. We urge further
  RV follow-up observations to precisely measure its mass, to enable
  precise transmission spectroscopic measurements in the future.

Title: Impact of crosshatch patterns in H2RGs on high-precision radial
velocity measurements: exploration of measurement and mitigation
    paths with the Habitable-Zone Planet Finder
Authors: Ninan, Joe P.; Mahadevan, Suvrath; Stefansson, Gudmundur;
   Bender, Chad; Roy, Arpita; Kaplan, Kyle F.; Fredrick, Connor; Metcalf,
   Andrew J.; Monson, Andrew; Terrien, Ryan; Ramsey, Lawrence W.; Diddams,
   Scott A.
Bibcode: 2019JATIS...5d1511N
Altcode: 2019arXiv190306614N
  Teledyne's H2RG detector images suffer from crosshatch like patterns,
  which arise from subpixel quantum efficiency (QE) variation. We present
  our measurements of this subpixel QE variation in the Habitable-Zone
  Planet Finder's H2RG detector. We present a simple model to estimate
  the impact of subpixel QE variations on the radial velocity and how a
  first-order correction can be implemented to correct for the artifact
  in the spectrum. We also present how the HPF's future upgraded laser
  frequency comb will enable us to implement this correction.

Title: Stellar spectroscopy in the near-infrared with a laser
    frequency comb
Authors: Metcalf, Andrew J.; Anderson, Tyler; Bender, Chad F.;
   Blakeslee, Scott; Brand, Wesley; Carlson, David R.; Cochran, William
   D.; Diddams, Scott A.; Endl, Michael; Fredrick, Connor; Halverson,
   Sam; Hickstein, Daniel D.; Hearty, Fred; Jennings, Jeff; Kanodia,
   Shubham; Kaplan, Kyle F.; Levi, Eric; Lubar, Emily; Mahadevan, Suvrath;
   Monson, Andrew; Ninan, Joe P.; Nitroy, Colin; Osterman, Steve; Papp,
   Scott B.; Quinlan, Franklyn; Ramsey, Larry; Robertson, Paul; Roy,
   Arpita; Schwab, Christian; Sigurdsson, Steinn; Srinivasan, Kartik;
   Stefansson, Gudmundur; Sterner, David A.; Terrien, Ryan; Wolszczan,
   Alex; Wright, Jason T.; Ycas, Gabriel
Bibcode: 2019Optic...6..233M
Altcode: 2019arXiv190200500M
  The discovery and characterization of exoplanets around nearby stars is
  driven by profound scientific questions about the uniqueness of Earth
  and our Solar System, and the conditions under which life could exist
  elsewhere in our Galaxy. Doppler spectroscopy, or the radial velocity
  (RV) technique, has been used extensively to identify hundreds of
  exoplanets, but with notable challenges in detecting terrestrial
  mass planets orbiting within habitable zones. We describe infrared RV
  spectroscopy at the 10 m Hobby-Eberly telescope that leverages a 30 GHz
  electro-optic laser frequency comb with nanophotonic supercontinuum to
  calibrate the Habitable Zone Planet Finder spectrograph. Demonstrated
  instrument precision &lt;10 cm/s and stellar RVs approaching 1 m/s
  open the path to discovery and confirmation of habitable zone planets
  around M-dwarfs, the most ubiquitous type of stars in our Galaxy.

Title: The NEID Doppler spectrometer at WIYN
Authors: Schwab, Christian; Bender, Chad; Blake, Cullen; Gong, Qian;
   Halverson, Sam; Hearty, Frederick; Hunting, Emily; Kanodia, Shubham;
   Liang, Ming; Logsdon, Sarah E.; Lubar, Emily; Mahadevan, Suvrath;
   McElwain, Michael; Monson, Andrew; Rajagopal, Jayadev; Ramsey,
   Lawrence; Robertson, Paul; Roy, Arpita; Stefansson, Gudmundur K.;
   Terrien, Ryan; Wright, Jason T.
Bibcode: 2019AAS...23340803S
Altcode:
  The US exoplanet science community urgently requires a radial velocity
  instrument with the sensitivity to observe rocky planets in the
  habitable zone, and follow-up the most promising TESS candidates. To
  address this need, we are building NEID, the new NN-Explore extreme
  precision Doppler spectrometer for the WIYN telescope at Kitt Peak
  Observatory. The guiding metric for the complete design was the
  instrument’s performance for its primary science goal, the Doppler
  observation of Earth-like exoplanets. It is based on a high optical
  performance Echelle spectrograph built around a classical white
  pupil relay with large beam size, and is fed by a high-scrambling
  fiber train. NEID covers the wavelength range from 380 - 930nm
  in a single frame with a resolution of ~100.000. The optics bench
  is housed in a vacuum chamber for environmental control, reaching
  sub-millikelvin temperature stability. Together with a sophisticated
  front end to provide excellent atmospheric dispersion correction
  and guiding stability, this forms a system with predicted Doppler
  precision of &lt;25 cm/s. In this talk, we will present the optical
  and optomechanical designs, and discuss the interplay of technical
  design choices and science demands.

Title: Ultrastable environment control for the NEID spectrometer:
    design and performance demonstration
Authors: Robertson, Paul; Anderson, Tyler; Stefansson, Gudmundur;
   Hearty, Frederick R.; Monson, Andrew; Mahadevan, Suvrath; Blakeslee,
   Scott; Bender, Chad; Ninan, Joe P.; Conran, David; Levi, Eric; Lubar,
   Emily; Cole, Amanda; Dykhouse, Adam; Kanodia, Shubham; Nitroy, Colin;
   Smolsky, Joseph; Tuggle, Demetrius; Blank, Basil; Nelson, Matthew;
   Blake, Cullen; Halverson, Samuel; Henderson, Chuck; Kaplan, Kyle F.;
   Li, Dan; Logsdon, Sarah E.; McElwain, Michael W.; Rajagopal, Jayadev;
   Ramsey, Lawrence W.; Roy, Arpita; Schwab, Christian; Terrien, Ryan;
   Wright, Jason T.
Bibcode: 2019JATIS...5a5003R
Altcode: 2019arXiv190207729R
  Two key areas of emphasis in contemporary experimental exoplanet science
  are the detailed characterization of transiting terrestrial planets and
  the search for Earth analog planets to be targeted by future imaging
  missions. Both of these pursuits are dependent on an order-of-magnitude
  improvement in the measurement of stellar radial velocities (RV),
  setting a requirement on single-measurement instrumental uncertainty
  of order 10 cm / s. Achieving such extraordinary precision on a
  high-resolution spectrometer requires thermomechanically stabilizing the
  instrument to unprecedented levels. We describe the environment control
  system (ECS) of the NEID spectrometer, which will be commissioned on
  the 3.5-m WIYN Telescope at Kitt Peak National Observatory in 2019,
  and has a performance specification of on-sky RV precision &lt;50 cm /
  s. Because NEID's optical table and mounts are made from aluminum,
  which has a high coefficient of thermal expansion, sub-milliKelvin
  temperature control is especially critical. NEID inherits its ECS from
  that of the Habitable-Zone Planet Finder (HPF), but with modifications
  for improved performance and operation near room temperature. Our
  full-system stability test shows the NEID system exceeds the already
  impressive performance of HPF, maintaining vacuum pressures below
  10<SUP> - 6</SUP> Torr and a root mean square (RMS) temperature
  stability better than 0.4 mK over 30 days. Our ECS design is fully
  open-source; the design of our temperature-controlled vacuum chamber
  has already been made public, and here we release the electrical
  schematics for our custom temperature monitoring and control system.

Title: Design and Performance of NEID Ultra-Stable Environmental
    Control System
Authors: Lubar, Emily; Mahadevan, Suvrath; Robertson, Paul; Stefansson,
   Gudmundur K.; Hearty, Frederick; Monson, Andrew; Bender, Chad; Ninan,
   Joe; Kanodia, Shubham; Nitroy, Colin; Blake, Cullen; Halverson, Sam;
   Logsdon, Sarah E.; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian;
   Wright, Jason T.
Bibcode: 2019AAS...23314602L
Altcode:
  NEID is an ultra-stable, optical spectrometer designed to achieve Radial
  Velocity (RV) precision on the order of 10cm/s. Achieving this level
  of measurement precision requires extreme thermo-mechanical stability
  within the instrument which we achieve by maintaining a vacuum on the
  order of microTorr as well as sub-milliKelvin temperature stability. In
  this poster, we will outline NEID's Environmental Control System (ECS)
  and Temperature Monitoring and Control (TMC) System, which were both
  inherited and improved upon from that of the Habitable-zone Planet
  Finder (HPF) infrared spectrograph. We have achieved our target
  stability by demonstrating &lt; 0.4mK RMS temperature variability
  over the course of a 30 day stability run in the lab. We expect
  our stability to improve at the observatory as the WIYN instrument
  room is more stable than our instrument development lab. NEID will be
  commissioned in midwinter 2019 at Kitt Peak National Observatory on the
  3.5m WIYN Telescope. It will serve the exoplanet community as a vital
  follow up asset for Earth-like planets targeted by the TESS survey.

Title: Science with NEID Guaranteed Time Observations
Authors: Wright, Jason T.; Bender, Chad; Blake, Cullen; Halverson,
   Sam; Hearty, Frederick; Mahadevan, Suvrath; McElwain, Michael; Ramsey,
   Lawrence; Roy, Arpita; Schwab, Christian
Bibcode: 2019AAS...23314028W
Altcode:
  The NEID spectrograph at the WIYN 3.5m telescope at Kitt Peak will
  be a facility instrument available to the precise radial velocity
  community via the NN-EXPLORE partnership between NASA and NOAO. The
  NEID instrument team will have 270 on-sky hours per year for 5 years
  of guaranteed time to conduct some of the novel science enabled by
  this instrument. In this poster, I describe the design and goals of
  the NEID team's science program with its Guaranteed Time Observations.

Title: Overview of the spectrometer optical fiber feed for the
    habitable-zone planet finder
Authors: Kanodia, Shubham; Mahadevan, Suvrath; Ramsey, Larry W.;
   Stefansson, Gudmundur K.; Monson, Andrew J.; Hearty, Frederick R.;
   Blakeslee, Scott; Lubar, Emily; Bender, Chad F.; Ninan, J. P.; Sterner,
   David; Roy, Arpita; Halverson, Samuel P.; Robertson, Paul M.
Bibcode: 2018SPIE10702E..6QK
Altcode: 2018arXiv180800557K
  The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber
  fed precision radial velocity (RV) spec- trograph working in the Near
  Infrared (NIR): 810 - 1280 nm. In this paper we present an overview of
  the preparation of the optical fibers for HPF. The entire fiber train
  from the telescope focus down to the cryostat is detailed. We also
  discuss the fiber polishing, splicing and its integration into the
  instrument using a fused silica puck. HPF was designed to be able to
  operate in two modes, High Resolution (HR- the only mode mode currently
  commissioned) and High Efficiency (HE). We discuss these fiber heads
  and the procedure we adopted to attach the slit on to the HR fibers.

Title: The NEID precision radial velocity spectrometer: port adapter
    overview, requirements, and test plan
Authors: Logsdon, Sarah E.; McElwain, Michael W.; Gong, Qian; Liang,
   Ming; Santoro, Fernando; Schwab, Christian; Bender, Chad; Blake,
   Cullen; Halverson, Samuel; Hearty, Fred; Hunting, Emily; Jaehnig,
   Kurt P.; Mahadevan, Suvrath; Monson, Andrew J.; Percival, Jeffrey W.;
   Rajagopal, Jayadev; Ramsey, Lawrence; Roy, Arpita; Smith, Michael P.;
   Terrien, Ryan C.; Timmermann, Erik; Willems, Phil; Wolf, Marsha J.;
   Wright, Jason
Bibcode: 2018SPIE10702E..67L
Altcode:
  The NEID spectrometer is an optical (380-930 nm), fiber-fed, precision
  Doppler spectrometer currently in de- velopment for the WIYN 3.5 m
  telescope at Kitt Peak National Observatory as part of the NN-EXPLORE
  partnership. Designed to achieve a radial velocity precision of &lt;
  30 cm/s, NEID will be sensitive enough to detect terrestrial-mass
  exoplanets around low-mass stars. Light from the target stars is focused
  by the telescope to a bent Cassegrain port at the edge of the primary
  mirror mechanical support. The specialized NEID "Port Adapter" system is
  mounted at this bent Cassegrain port and is responsible for delivering
  the incident light from the telescope to the NEID fibers. In order to
  provide stable, high-quality images to the science instrument, the Port
  Adapter houses several sub-components designed to acquire the target
  stars, correct for atmospheric dis- persion, stabilize the light onto
  the science fibers, and calibrate the spectrometer by injecting known
  wavelength sources such as a laser frequency comb. Here we provide an
  overview of the overall opto-mechanical design and system requirements
  of the Port Adapter. We also describe the development of system error
  budgets and test plans to meet those requirements.

Title: The NEID precision radial velocity spectrometer: optical
    design of the port adapter and ADC
Authors: Schwab, Christian; Liang, Ming; Gong, Qian; Bender, Chad;
   Blake, Cullen; Halverson, Samuel; Harbeck, Daniel; Hearty, Fred;
   Hunting, Emily; Jaehnig, Kurt P.; Logsdon, Sarah E.; Mahadevan,
   Suvrath; McElwain, Michael W.; Monson, Andrew J.; Percival, Jeffrey W.;
   Rajagopal, Jayadev; Ramsey, Lawrence; Robertson, Paul M.; Roy, Arpita;
   Santoro, Fernando; Smith, Michael P.; Terrien, Ryan C.; Timmermann,
   Erik; Willems, Phil; Wolf, Marsha J.; Wright, Jason
Bibcode: 2018SPIE10702E..71S
Altcode:
  NEID is a new extreme precision Doppler spectrometer for the WIYN
  telescope. It is fiber fed and employs a classical white pupil Echelle
  configuration. NEID has a fiber aperture of only 0.92" on sky in
  high-resolution mode, and its tight radial velocity error budget
  resulted in very stringent stability requirements for the input
  illumination of the spectrograph optics. Consequently, the demands
  on the fiber injection are challenging. In this paper, we describe
  the layout and optical design of the injection module, including a
  broadband, high image quality relay and a high-performance atmospheric
  dispersion corrector (ADC) across the bandwidth of 380 - 930 nm.

Title: Completion and performance of the Hobby-Eberly Telescope wide
    field upgrade
Authors: Hill, Gary J.; Drory, Niv; Good, John M.; Lee, Hanshin;
   Vattiat, Brian L.; Kriel, Herman; Ramsey, Jason; Bryant, Randy; Fowler,
   Jim; Landriau, Martin; Leck, Ron; Mrozinski, Emily; Odewahn, Stephen;
   Shetrone, Matthew; Westfall, Amy; Terrazas, Eusebio; Balderrama,
   Edmundo; Bevins, Emily; Buetow, Brent; Caldwell, John; Damm, George;
   MacQueen, Phillip; Martin, Jerry; Martin, Amanda; Pautzke, Justin;
   Smither, Katie; Rostopchin, Sergey; Smith, Greg; Spencer, Renny;
   Armandroff, Taft; Gebhardt, Karl; Ramsey, Lawrence W.
Bibcode: 2018SPIE10700E..0PH
Altcode:
  The Hobby-Eberly Telescope (HET) is an innovative large telescope
  with 10 meter aperture, located in West Texas at the McDonald
  Observatory. The HET operates with a fixed segmented primary and
  has a tracker, which moves the fourmirror corrector and prime focus
  instrument package to track the sidereal and non-sidereal motions
  of objects. We have completed a major multi-year upgrade of the HET
  that has substantially increased the field of view to 22 arcminutes by
  replacing the optical corrector, tracker, and prime focus instrument
  package and by developing a new telescope control system. The upgrade
  has replaced all hardware and systems except for the structure,
  enclosure, and primary mirror. The new, reinvented wide-field HET feeds
  the revolutionary Visible Integral-field Replicable Unit Spectrograph
  (VIRUS‡), fed by 35,000 fibers, in support of the Hobby-Eberly
  Telescope Dark Energy Experiment (HETDEX§), a new low resolution
  spectrograph (LRS2), the Habitable Zone Planet Finder (HPF), and
  the upgraded high resolution spectrograph (HRS2). The HET Wide Field
  Upgrade has now been commissioned and has been in science operations
  since mid 2016 and in full science operations from mid 2018. This
  paper reviews and summarizes the upgrade, lessons learned, and the
  operational performance of the new HET.

Title: The Habitable Zone Planet Finder: Precision NIR Radial
    Velocities during Testing &amp; Commissioning
Authors: Ninan, Joe Philip; Roy, Arpita; Terrien, Ryan; Kaplan, Kyle;
   Bender, Chad; Monson, Andy; Robertson, Paul; Stefansson, Gudmundur;
   Kanodia, Shubham; Halverson, Sam; Mahadevan, Suvrath; Hearty, Fred;
   Wright, Jason T.; Ramsey, Lawrence; Blakeslee, Scott; Anderson, Tyler;
   Schwab, Christian
Bibcode: 2018AAS...23115218N
Altcode:
  The Habitable Zone Planet Finder (HPF) is a fiber-fed near-infrared
  (0.8 to 1.24 microns) spectrometer designed for high stability for
  precision Doppler radial velocity surveys using the 10m Hobby Eberly
  Telescope. We discuss results obtained during the lab testing and
  commissioning phase that show the solar spectrum and the key parameters
  of the instrument, and demonstrate that the HPF fibers track each other
  to sub-meter per second relative Doppler radial velocity precision. We
  will also discuss the capabilities of HPF, as well as the reduction
  challenges in the infrared, and our solutions to these challenges.

Title: NEID Port Adapter: Design and Verification Plan
Authors: Logsdon, Sarah E.; McElwain, Michael; McElwain, Michael W.;
   Gong, Qian; Bender, Chad; Halverson, Samuel; Hearty, Fred; Hunting,
   Emily; Jaehnig, Kurt; Liang, Ming; Mahadevan, Suvrath; Monson, A. J.;
   Percival, Jeffrey; Rajagopal, Jayadev; Ramsey, Lawrence; Roy, Arpita;
   Santoro, Fernando; Schwab, Christian; Smith, Michael; Wolf, Marsha;
   Wright, Jason
Bibcode: 2018AAS...23115208L
Altcode:
  The NEID spectrograph is an optical (380-930 nm), fiber-fed, precision
  Doppler spectrograph currently in development for the 3.5 m WIYN
  Telescope at Kitt Peak National Observatory. Designed to achieve a
  radial velocity precision of &lt;30 cm/s, NEID will be sensitive enough
  to detect terrestrial-mass exoplanets around low-mass stars. Light from
  the target stars is focused by the telescope to a bent-Cassegrain port
  at the edge of the primary mirror mechanical support. The specialized
  NEID “Port Adapter” system is mounted at this bent-Cassegrain
  port and is responsible for delivering the incident light from the
  telescope to the NEID fibers. In order to provide stable, high-quality
  images to the science instrument, the Port Adapter houses several
  subcomponents designed to acquire the target stars, correct for
  atmospheric dispersion, stabilize the light onto the science fibers,
  and calibrate the spectrograph by injecting known wavelength sources
  such as a laser frequency comb. Here we describe the overall design
  of the Port Adapter and outline the development of calibration tools
  and an on-sky test plan to verify the performance of the atmospheric
  dispersion corrector (ADC). We also discuss the development of an error
  budget and test requirements to ensure high-precision centroiding onto
  the NEID science fibers using a system of coherent fiber bundles.

Title: NEID: A High Precision Radial Velocity Spectrograph for the
    WIYN 3.5-m Telescope
Authors: Allen, Lori E.; Wright, Jason; Rajagopal, Jayadev; Santoro,
   Fernando; Liang, Ming; Timmerman, Erik; Christensen, Robert; Hunting,
   Emily; Wolf, Marsha; Jaehnig, Kurt; Percival, Jeffrey; Smith, Michael;
   Mahadevan, Suvrath; Hearty, Fred; Bender, Chad; Blake, Cullen; Logsdon,
   Sarah E.; Akeson, Rachel; Capps, Richard W.; Callas, John; Willems,
   Phillip A.; McElwain, Michael; McElwain, Michael W.; Basten, Fabienne;
   Monson, Andy; Stefansson, Gudmundur; Ramsey, Larry; Ninan, Joe;
   Blakeslee, Scott; Kaplan, Kyle; Halverson, Sam; Roy, Arpita; Terrien,
   Ryan; Robertson, Paul; Schwab, Christian; Rud, Mayer; Kanodia, Shubham
Bibcode: 2018AAS...23124608A
Altcode:
  NEID will be an ultra-stable optical high resolution echelle
  spectrograph on the 3.5 WIYN telescope at Kitt Peak National
  Observatory, with a design goal of &lt; 30 cm/s instrumental
  stability. It is part of a joint NSF-NASA initiative (NN-EXPLORE)
  to support ground-based Doppler velocimetry of nearby stars for the
  detection and characterization of rocky exoplanets around nearby
  stars. Here we describe the instrument's design, construction and
  commissioning schedule, capabilities, and future opportunities to
  apply for public time on this flagship Doppler instrument.

Title: HPF: The Habitable Zone Planet Finder at the Hobby-Eberly
    Telescope
Authors: Wright, Jason T.; Mahadevan, Suvrath; Hearty, Fred; Monson,
   Andy; Stefansson, Gudmundur; Ramsey, Larry; Ninan, Joe; Bender, Chad;
   Kaplan, Kyle; Roy, Arpita; Terrien, Ryan; Robertson, Paul; Halverson,
   Sam; Schwab, Christian; Kanodia, Shubham
Bibcode: 2018AAS...23124645W
Altcode:
  The Habitable Zone Planet Finder (HPF) is an ultra-stable NIR (ZYJ)
  high resolution echelle spectrograph on the 10-m Hobby-Eberly Telescope
  capable of 1-3 m/s Doppler velocimetry on nearby late M dwarfs
  (M4-M9). This precision is sufficient to detect terrestrial planets
  in the Habitable Zones of these relatively unexplored stars. Here we
  present its capabilities and early commissioning results.

Title: Proxima Centauri as a Benchmark for Stellar Activity Indicators
    in the Near-infrared
Authors: Robertson, Paul; Bender, Chad; Mahadevan, Suvrath; Roy,
   Arpita; Ramsey, Lawrence W.
Bibcode: 2016ApJ...832..112R
Altcode: 2016arXiv160806291R
  A new generation of dedicated Doppler spectrographs will attempt to
  detect low-mass exoplanets around mid- to late M stars at near-infrared
  (NIR) wavelengths, where those stars are brightest and have the most
  Doppler information content. A central requirement for the success
  of these instruments is to properly measure the component of radial
  velocity (RV) variability contributed by stellar magnetic activity
  and to account for it in exoplanet models of RV data. The wavelength
  coverage for many of these new instruments will not include the Ca
  II H&amp;K or Hα lines, the most frequently used absorption-line
  tracers of magnetic activity. Thus, it is necessary to define and
  characterize NIR activity indicators for mid- to late M stars in order
  to provide simultaneous activity metrics for NIR RV data. We have used
  the high-cadence UVES observations of the M5.5 dwarf Proxima Centauri
  from Fuhrmeister et al. to compare the activity sensitivity of eight
  NIR atomic lines to that of Hα. We find that equivalent-width-type
  measurements of the NIR K I doublet and the Ca II NIR triplet
  are excellent proxies for the canonical optical tracers. The Ca II
  triplet will be acquired by most of the new and upcoming NIR Doppler
  spectrographs, offering a common, reliable indicator of activity.

Title: A Versatile Technique to Enable Sub-milli-Kelvin Instrument
Stability for Precise Radial Velocity Measurements: Tests with the
    Habitable-zone Planet Finder
Authors: Stefansson, Gudmundur; Hearty, Frederick; Robertson, Paul;
   Mahadevan, Suvrath; Anderson, Tyler; Levi, Eric; Bender, Chad; Nelson,
   Matthew; Monson, Andrew; Blank, Basil; Halverson, Samuel; Henderson,
   Chuck; Ramsey, Lawrence; Roy, Arpita; Schwab, Christian; Terrien, Ryan
Bibcode: 2016ApJ...833..175S
Altcode: 2016arXiv161006216S
  Insufficient instrument thermomechanical stability is one of the many
  roadblocks for achieving 10 cm s<SUP>-1</SUP> Doppler radial velocity
  precision, the precision needed to detect Earth-twins orbiting
  solar-type stars. Highly temperature and pressure stabilized
  spectrographs allow us to better calibrate out instrumental
  drifts, thereby helping in distinguishing instrumental noise from
  astrophysical stellar signals. We present the design and performance of
  the Environmental Control System (ECS) for the Habitable-zone Planet
  Finder (HPF), a high-resolution (R = 50,000) fiber-fed near-infrared
  (NIR) spectrograph for the 10 {{m}} Hobby-Eberly Telescope at McDonald
  Observatory. HPF will operate at 180 {{K}}, driven by the choice of
  an H2RG NIR detector array with a 1.7 μ {{m}} cutoff. This ECS has
  demonstrated 0.6 {mK} rms stability over 15 days at both 180 and 300
  {{K}}, and maintained high-quality vacuum (\lt {10}<SUP>-7</SUP>
  {Torr}) over months, during long-term stability tests conducted
  without a planned passive thermal enclosure surrounding the vacuum
  chamber. This control scheme is versatile and can be applied as
  a blueprint to stabilize future NIR and optical high-precision
  Doppler instruments over a wide temperature range from ∼77 {{K}}
  to elevated room temperatures. A similar ECS is being implemented
  to stabilize NEID, the NASA/NSF NN-EXPLORE spectrograph for the 3.5
  {{m}} WIYN telescope at Kitt Peak, operating at 300 {{K}}. A [<A
  href="https://scholarsphere.psu.edu/files/7p88cg66f">full SolidWorks
  3D-CAD model</A>] and a comprehensive parts list of the HPF ECS are
  included with this manuscript to facilitate the adaptation of this
  versatile environmental control scheme in the broader astronomical
  community. <P />Certain commercial equipment, instruments, or materials
  are identified in this paper in order to specify the experimental
  procedure adequately. Such identification is not intended to imply
  recommendation or endorsement by the National Institute of Standards
  and Technology, nor is it intended to imply that the materials or
  equipment identified are necessarily the best available for the purpose.

Title: Measuring extended red sensitivity in a 1.7μm-cutoff HgCdTe
    detector array
Authors: Terrien, Ryan C.; Monson, Andrew J.; Mahadevan, Suvrath;
   Bender, Chad; Halverson, Samuel P.; Ramsey, Larry
Bibcode: 2016SPIE.9915E..1QT
Altcode:
  Infrared detectors with cutoff wavelengths of 1.7 μm have much
  lower sensitivity to thermal background contamination than those with
  longer cutoff wavelengths. This low sensitivity offers the attractive
  possibility of reducing the need for fully cryogenic systems for
  YJH-band work, offering the potential for "warm-pupil" instrumentation
  that nonetheless reduces detected thermal background to the level of
  dark current. However, residual sensitivity beyond the cutoff wavelength
  is not well characterized, and may preclude the implementation of
  such warm-pupil instruments. We describe an experiment to evaluate the
  long-wavelength sensitivity tail of a 1.7 µm-cutoff HAWAII-2RG array
  using a thermal blocking filter. Our results suggest the possibility
  of measurable red sensitivity beyond 2 μm. Ongoing improvements
  will confirm and refine this measurement. The thermal blocking filter
  offers the prospect of warm-pupil NIR instrument operation, which is
  particularly valuable for cost-effective and efficient testing systems:
  it has facilitated NIR detector characterization and will enable crucial
  laboratory tests of laser frequency comb calibration systems and other
  NIR calibration sources.

Title: A comprehensive radial velocity error budget for next
    generation Doppler spectrometers
Authors: Halverson, Samuel; Terrien, Ryan; Mahadevan, Suvrath; Roy,
   Arpita; Bender, Chad; Stefánsson, Gudmundur K.; Monson, Andrew;
   Levi, Eric; Hearty, Fred; Blake, Cullen; McElwain, Michael; Schwab,
   Christian; Ramsey, Lawrence; Wright, Jason; Wang, Sharon; Gong, Qian;
   Roberston, Paul
Bibcode: 2016SPIE.9908E..6PH
Altcode: 2016arXiv160705634H
  We describe a detailed radial velocity error budget for the NASA-NSF
  Extreme Precision Doppler Spectrometer instrument concept NEID
  (NN-explore Exoplanet Investigations with Doppler spectroscopy). Such
  an instrument performance budget is a necessity for both identifying
  the variety of noise sources currently limiting Doppler measurements,
  and estimating the achievable performance of next generation exoplanet
  hunting Doppler spectrometers. For these instruments, no single source
  of instrumental error is expected to set the overall measurement
  floor. Rather, the overall instrumental measurement precision is
  set by the contribution of many individual error sources. We use a
  combination of numerical simulations, educated estimates based on
  published materials, extrapolations of physical models, results from
  laboratory measurements of spectroscopic subsystems, and informed
  upper limits for a variety of error sources to identify likely sources
  of systematic error and construct our global instrument performance
  error budget. While natively focused on the performance of the NEID
  instrument, this modular performance budget is immediately adaptable
  to a number of current and future instruments. Such an approach is an
  important step in charting a path towards improving Doppler measurement
  precisions to the levels necessary for discovering Earth-like planets.

Title: Ultra-stable temperature and pressure control for the
    Habitable-zone Planet Finder spectrograph
Authors: Stefánsson, Gudmundur K.; Hearty, Frederick R.; Robertson,
   Paul M.; Levi, Eric I.; Mahadevan, Suvrath; Anderson, Tyler B.; Monson,
   Andrew J.; Bender, Chad F.; Halverson, Samuel P.; Li, Yiting; Ramsey,
   Lawrence W.; Roy, Arpita; Schwab, Christian; Terrien, Ryan C.; Nelson,
   Matthew J.; Blank, Basil
Bibcode: 2016SPIE.9908E..71S
Altcode:
  We present recent long-term stability test results of the cryogenic
  Environmental Control System (ECS) for the Habitable zone Planet Finder
  (HPF), a near infrared ultra-stable spectrograph operating at 180
  Kelvin. Exquisite temperature and pressure stability is required for
  high precision radial velocity (&lt; 1m=s) instruments, as temperature
  and pressure variations can easily induce instrumental drifts of several
  tens-to-hundreds of meters per second. Here we present the results from
  long-term stability tests performed at the 180K operating temperature
  of HPF, demonstrating that the HPF ECS is stable at the 0:6mK level
  over 15-days, and &lt;10<SUP>-7</SUP> Torr over months.

Title: The instrument control software package for the Habitable-Zone
    Planet Finder spectrometer
Authors: Bender, Chad F.; Robertson, Paul; Stefansson, Gudmundur Kari;
   Monson, Andrew; Anderson, Tyler; Halverson, Samuel; Hearty, Frederick;
   Levi, Eric; Mahadevan, Suvrath; Nelson, Matthew; Ramsey, Larry; Roy,
   Arpita; Schwab, Christian; Shetrone, Matthew; Terrien, Ryan
Bibcode: 2016SPIE.9913E..38B
Altcode:
  We describe the Instrument Control Software (ICS) package that we have
  built for The Habitable-Zone Planet Finder (HPF) spectrometer. The ICS
  controls and monitors instrument subsystems, facilitates communication
  with the Hobby-Eberly Telescope facility, and provides user interfaces
  for observers and telescope operators. The backend is built around the
  asynchronous network software stack provided by the Python Twisted
  engine, and is linked to a suite of custom hardware communication
  protocols. This backend is accessed through Python-based command-line
  and PyQt graphical frontends. In this paper we describe several of the
  customized subsystem communication protocols that provide access to
  and help maintain the hardware systems that comprise HPF, and show how
  asynchronous communication benefits the numerous hardware components. We
  also discuss our Detector Control Subsystem, built as a set of custom
  Python wrappers around a C-library that provides native Linux access
  to the SIDECAR ASIC and Hawaii-2RG detector system used by HPF. HPF
  will be one of the first astronomical instruments on sky to utilize
  this native Linux capability through the SIDECAR Acquisition Module
  (SAM) electronics. The ICS we have created is very flexible, and we
  are adapting it for NEID, NASA's Extreme Precision Doppler Spectrometer
  for the WIYN telescope; we will describe this adaptation, and describe
  the potential for use in other astronomical instruments.

Title: Design of NEID, an extreme precision Doppler spectrograph
    for WIYN
Authors: Schwab, C.; Rakich, A.; Gong, Q.; Mahadevan, S.; Halverson,
   S. P.; Roy, A.; Terrien, R. C.; Robertson, P. M.; Hearty, F. R.;
   Levi, E. I.; Monson, A. J.; Wright, J. T.; McElwain, M. W.; Bender,
   C. F.; Blake, C. H.; Stürmer, J.; Gurevich, Y. V.; Chakraborty, A.;
   Ramsey, L. W.
Bibcode: 2016SPIE.9908E..7HS
Altcode:
  We have developed an optical design for a high resolution spectrograph
  in response to NASA's call for an extreme precision Doppler spectrometer
  (EPDS) for the WIYN telescope. Our instrument covers a wavelength
  range of 380 to 930 nm using a single detector and with a resolution
  of 100,000. To deliver the most stable spectrum, we avoid the use of
  an image slicer, in favor of a large (195 mm diameter) beam footprint
  on a 1x2 mosaic R4 Echelle grating. The optical design is based on
  a classic white pupil layout, with a single parabolic mirror that is
  used as the main and transfer collimator. Cross dispersion is provided
  by a single large PBM2Y glass prism. The refractive camera consists of
  only four rotationally symmetric lenses made from i-Line glasses, yet
  delivers very high image quality over the full spectral bandpass. We
  present the optical design of the main spectrograph bench and discuss
  the design trade-offs and expected performance.

Title: A system to provide sub-milliKelvin temperature control at
    T 300K for extreme precision optical radial velocimetry
Authors: Robertson, Paul M.; Hearty, Frederick R.; Anderson, Tyler B.;
   Stefánsson, Gudmundur K.; Levi, Eric I.; Bender, Chad F.; Mahadevan,
   Suvrath; Halverson, Samuel P.; Monson, Andrew J.; Ramsey, Lawrence W.;
   Roy, Arpita; Schwab, Christian; Terrien, Ryan C.; Nelson, Matthew J.;
   Blank, Basil
Bibcode: 2016SPIE.9908E..62R
Altcode:
  We present preliminary results for the environmental control system
  from NEID, our instrument concept for NASA's Extreme Precision Doppler
  Spectrograph, which is now in development. Exquisite temperature
  control is a requirement for Doppler spectrographs, as small temperature
  shifts induce systematic Doppler shifts far exceeding the instrumental
  specifications. Our system is adapted from that of the Habitable Zone
  Planet Finder instrument, which operates at a temperature of 180K.We
  discuss system modifications for operation at T 300K, and show data
  demonstrating sub-mK stability over two weeks from a full-scale
  system test.

Title: Deployment of the Hobby-Eberly Telescope wide-field upgrade
Authors: Hill, Gary J.; Drory, Niv; Good, John M.; Lee, Hanshin;
   Vattiat, Brian L.; Kriel, Herman; Ramsey, Jason; Bryant, Randy;
   Elliot, Linda; Fowler, Jim; Häuser, Marco; Landiau, Martin; Leck, Ron;
   Odewahn, Stephen; Perry, Dave; Savage, Richard; Schroeder Mrozinski,
   Emily; Shetrone, Matthew; DePoy, D. L.; Prochaska, Travis; Marshall,
   J. L.; Damm, George; Gebhardt, Karl; MacQueen, Phillip J.; Martin,
   Jerry; Armandroff, Taft; Ramsey, Lawrence W.
Bibcode: 2016SPIE.9906E..06H
Altcode:
  The Hobby-Eberly Telescope (HET) is an innovative large telescope,
  located in West Texas at the McDonald Observatory. The HET operates with
  a fixed segmented primary and has a tracker, which moves the four-mirror
  corrector and prime focus instrument package to track the sidereal and
  non-sidereal motions of objects. We have completed a major multi-year
  upgrade of the HET that has substantially increased the pupil size
  to 10 meters and the field of view to 22 arcminutes by replacing the
  corrector, tracker, and prime focus instrument package. The new wide
  field HET will feed the revolutionary integral field spectrograph called
  VIRUS, in support of the Hobby-Eberly Telescope Dark Energy Experiment
  (HETDEX<SUP>§</SUP>), a new low resolution spectrograph (LRS2), an
  upgraded high resolution spectrograph (HRS2), and later the Habitable
  Zone Planet Finder (HPF). The upgrade is being commissioned and this
  paper discusses the completion of the installation, the commissioning
  process and the performance of the new HET.

Title: VizieR Online Data Catalog: Stellar noise for 4529 Kepler
    solar-type dwarfs (Gilliland+, 2015)
Authors: Gilliland, R. L.; Chaplin, W. J.; Jenkins, J. M.; Ramsey,
   L. W.; Smith, J. C.
Bibcode: 2015yCat..51500133G
Altcode:
  The NASA Kepler Mission has left an indelible imprint on the research
  of exoplanet and stellar properties for a large number of stars
  (~150000), over four years. <P />Our earlier study (Gilliland et al.,
  2011ApJS..197....6G; Paper I) provided a discussion about the Kepler
  Mission noise properties. The earlier study over the first six quarters
  of Kepler data is extended to the full four years ultimately comprising
  the mission. <P />A total of 4529 stars (see Table3) brighter than
  K<SUB>p</SUB>=12.5 met the selection criteria for solar-type dwarfs
  as detailed in Paper I (Gilliland et al., 2011ApJS..197....6G). <P
  />(1 data file).

Title: Kepler Mission Stellar and Instrument Noise Properties
    Revisited
Authors: Gilliland, Ronald L.; Chaplin, William J.; Jenkins, Jon M.;
   Ramsey, Lawrence W.; Smith, Jeffrey C.
Bibcode: 2015AJ....150..133G
Altcode: 2015arXiv150805054G
  An earlier study of the Kepler Mission noise properties on timescales
  of primary relevance to detection of exoplanet transits found that
  higher than expected noise followed, to a large extent, from the stars
  rather than instrument or data analysis performance. The earlier study
  over the first six quarters of Kepler data is extended to the full
  four years ultimately comprising the mission. Efforts to improve the
  pipeline data analysis have been successful in reducing noise levels
  modestly as evidenced by smaller values derived from the current data
  products. The new analyses of noise properties on transit timescales
  show significant changes in the component attributed to instrument
  and data analysis, with essentially no change in the inferred stellar
  noise. We also extend the analyses to timescales of several days,
  instead of several hours to better sample stellar noise that follows
  from magnetic activity. On the longer timescale there is a shift in
  stellar noise for solar-type stars to smaller values in comparison to
  solar values.

Title: An Efficient, Compact, and Versatile Fiber Double Scrambler
    for High Precision Radial Velocity Instruments
Authors: Halverson, Samuel; Roy, Arpita; Mahadevan, Suvrath; Ramsey,
   Lawrence; Levi, Eric; Schwab, Christian; Hearty, Fred; MacDonald, Nick
Bibcode: 2015ApJ...806...61H
Altcode: 2015arXiv150507463H
  We present the design and test results of a compact optical
  fiber double-scrambler for high-resolution Doppler radial velocity
  instruments. This device consists of a single optic: a high-index n
  ∼ 2 ball lens that exchanges the near and far fields between two
  fibers. When used in conjunction with octagonal fibers, this device
  yields very high scrambling gains (SGs) and greatly desensitizes the
  fiber output from any input illumination variations, thereby stabilizing
  the instrument profile of the spectrograph and improving the Doppler
  measurement precision. The system is also highly insensitive to input
  pupil variations, isolating the spectrograph from telescope illumination
  variations and seeing changes. By selecting the appropriate glass and
  lens diameter the highest efficiency is achieved when the fibers are
  practically in contact with the lens surface, greatly simplifying
  the alignment process when compared to classical double-scrambler
  systems. This prototype double-scrambler has demonstrated significant
  performance gains over previous systems, achieving SGs in excess of
  10,000 with a throughput of ∼87% using uncoated Polymicro octagonal
  fibers. Adding a circular fiber to the fiber train further increases
  the SG to &gt;20,000, limited by laboratory measurement error. While
  this fiber system is designed for the Habitable-zone Planet Finder
  spectrograph, it is more generally applicable to other instruments
  in the visible and near-infrared. Given the simplicity and low cost,
  this fiber scrambler could also easily be multiplexed for large
  multi-object instruments.

Title: Toward Understanding Stellar Radial Velocity Jitter as a
Function of Wavelength: The Sun as a Proxy
Authors: Marchwinski, Robert C.; Mahadevan, Suvrath; Robertson, Paul;
   Ramsey, Lawrence; Harder, Jerald
Bibcode: 2015ApJ...798...63M
Altcode: 2014arXiv1410.7379M
  Using solar spectral irradiance measurements from the SORCE spacecraft
  and the F/F' technique, we have estimated the radial velocity (RV)
  scatter induced on the Sun by stellar activity as a function of
  wavelength. Our goal was to evaluate the potential advantages of
  using new near-infrared (NIR) spectrographs to search for low-mass
  planets around bright F, G, and K stars by beating down activity
  effects. Unlike M dwarfs, which have higher fluxes and therefore greater
  RV information content in the NIR, solar-type stars are brightest at
  visible wavelengths, and, based solely on information content, are
  better suited to traditional optical RV surveys. However, we find that
  the F/F' estimated RV noise induced by stellar activity is diminished by
  up to a factor of four in the NIR versus the visible. Observations with
  the upcoming future generation of NIR instruments can be a valuable
  addition to the search for low-mass planets around bright FGK stars
  in reducing the amount of stellar noise affecting RV measurements.

Title: Characterizing M dwarf planet hosts and enabling precise
    radial velocities in the near-infrared
Authors: Terrien, Ryan; Mahadevan, Suvrath; Deshpande, Rohit; Bender,
   Chad F.; Ramsey, Lawrence W.
Bibcode: 2015AAS...22511206T
Altcode:
  M dwarfs account for ~70% of the stars in the Solar neighborhood and
  represent a rich frontier for upcoming surveys for M dwarf planets,
  including the Habitable Zone Planet Finder (HPF) radial velocity
  (RV) survey, which will search for planets around nearby M dwarfs
  in the near-infrared (NIR). Crucial for the construction of target
  lists for these surveys and the interpretation of survey results
  is the development of techniques for measuring M dwarf stellar
  composition, activity, and age. Measurements of these parameters are
  made difficult by the complexity of M dwarf spectra and their slow
  evolution once on the main sequence. I will outline our application
  of empirically-calibrated techniques for measuring [Fe/H], which has
  enabled our development of new activity and age indicators based on NIR
  spectra from the low-resolution IRTF-SpeX spectrograph. I will discuss
  the implications of these new measurements, which hint at the effects
  of alpha element enrichment and youth, and reveal a strong connection
  between metallicity and stellar infrared luminosity. These new
  techniques allow refinements of existing calibrations, and contribute
  to a catalog of the stellar parameters of ~900 M dwarfs that will be
  an invaluable resource for the upcoming HPF survey.I will also outline
  developments in simulations and design for HPF, which will be among
  the first of the next generation of NIR precision RV instruments on
  large telescopes. I will describe an end-to-end instrument simulator
  that has helped optimize the HPF spectral coverage and instrumental
  configuration, the extensive study of vacuum phase holographic grating
  cross-disperser that will optimize the efficiency of HPF, and the
  precise characterization of the physical properties and behavior of the
  HPF H2RG near-infrared detector array. This hardware work will enable
  the 1-3m/s precision required for HPF to find Earth-mass planets in
  the habitable zones of nearby M dwarfs, and the stellar parameters
  in the M dwarf catalog will provide the information necessary to
  optimize the scientific yield of HPF by ensuring a large number of
  well-characterized planet hosts.

Title: The Habitable-zone Planet Finder (HPF): Achieving high
    precision radial velocities and mitigating stellar activity noise
Authors: Mahadevan, Suvrath; Ramsey, Lawrence W.; Terrien, Ryan;
   Robertson, Paul; Marchwinski, Robert C.; Hearty, Fred; Levi, Eric;
   Kári Stefánsson, Gudmundur; Bender, Chad F.; Halverson, Samuel;
   Roy, Arpita; Nelson, Matt; Schwab, Christian
Bibcode: 2015AAS...22525823M
Altcode:
  HPF is a stabilized, fiber-fed, near infrared (NIR) spectrograph
  currently being built at Penn State for the 10m Hobby-Eberly Telescope
  (HET). HPF will be capable of discovering low mass planets in the
  Habitable Zones of mid-late M dwarfs via radial velocity (RV). We
  discuss the development of critical sub-systems like our high-stability
  temperature control system, vacuum cryostat, and implementation of
  new wavelength calibration techniques. The design of the HET enables
  queue-scheduled operation, but its variable pupil requires attention
  to both near- and far-field fiber scrambling, which we accomplish
  with double scramblers and octagonal fibers.HPF will provide partial
  bandwith coverage of the information-rich z, Y and J NIR bands at a
  spectral resolving power of R∼50,000. While stellar activity induced
  RV noise is lower in the NIR than at visible wavelengths, we have
  carefully included NIR activity indicators in our spectral bandpass
  to help discriminate stellar activity from real planet signals, as
  has been recently demonstrated for Gliese 581 and Gliese 667C systems.

Title: The habitable-zone planet finder calibration system
Authors: Halverson, Samuel; Mahadevan, Suvrath; Ramsey, Lawrence;
   Terrien, Ryan; Roy, Arpita; Schwab, Christian; Bender, Chad; Hearty,
   Fred; Levi, Eric; Osterman, Steve; Ycas, Gabe; Diddams, Scott
Bibcode: 2014SPIE.9147E..7ZH
Altcode: 2014arXiv1408.3632H
  We present the design concept of the wavelength calibration system for
  the Habitable-zone Planet Finder instrument (HPF), a precision radial
  velocity (RV) spectrograph designed to detect terrestrial-mass planets
  around M-dwarfs. HPF is a stabilized, fiber-fed, R~50,000 spectrograph
  operating in the near-infrared (NIR) z/Y/J bands from 0.84 to 1.3
  microns. For HPF to achieve 1 m s<SUP>-1</SUP> or better measurement
  precision, a unique calibration system, stable to several times better
  precision, will be needed to accurately remove instrumental effects at
  an unprecedented level in the NIR. The primary wavelength calibration
  source is a laser frequency comb (LFC), currently in development
  at NIST Boulder, discussed separately in these proceedings. The LFC
  will be supplemented by a stabilized single-mode fiber Fabry-Perot
  interferometer reference source and Uranium-Neon lamp. The HPF
  calibration system will combine several other new technologies developed
  by the Penn State Optical-Infrared instrumentation group to improve
  RV measurement precision including a dynamic optical coupling system
  that significantly reduces modal noise effects. Each component has been
  thoroughly tested in the laboratory and has demonstrated significant
  performance gains over previous NIR calibration systems.

Title: Scrambling and modal noise mitigation in the Habitable Zone
    Planet Finder fiber feed
Authors: Roy, Arpita; Halverson, Samuel; Mahadevan, Suvrath; Ramsey,
   Lawrence W.
Bibcode: 2014SPIE.9147E..6BR
Altcode:
  We present the baseline fiber feed design for the Habitable-zone
  Planet Finder (HPF), a precision radial velocity (RV) spectrograph
  designed to detect Earth analogs around M-dwarfs. HPF is a stabilized,
  fiber-fed, R∼50,000 spectrograph operating in the near-infrared
  (NIR) from 0.82 to 1.3 µm, and will be deployed on the Hobby- Eberly
  Telescope (HET) in Texas. While the essential function of the optical
  fibers is to deliver high throughput, this mode of light transport also
  provides the opportunity to introduce radial and azimuthal scrambling,
  which boosts instrument stability and thereby RV precision. Based
  on the unique requirements of HPF on the HET, we present initial
  tests showing very high scrambling gains via a compact scrambler in
  conjunction with octagonal fibers. Conversely, the propagation of light
  through the fibers injects modal noise, which can limit achievable RV
  precision. Laboratory tests of a custom-built mechanical agitator show
  significant gains over a static fiber feed. Overall, the fiber feed
  is designed to provide high relative throughput, excellent scrambling,
  and reliable modal noise suppression. We will also attempt to minimize
  focal ratio degradation (FRD) to the extent possible with the chosen
  configuration. HPF inculcates several other new technologies developed
  by the Penn State Optical-Infrared instrumentation group, including a
  rigorous calibration system, which are discussed separately in these
  proceedings.

Title: Near field modal noise reduction using annealed optical fiber
Authors: Osterman, Steven N.; Ycas, Gabriel G.; Donaldson, Chelsea;
   Diddams, Scott A.; Mahadevan, Suvrath; Ramsey, Lawrence W.; Plavchan,
   Peter P.
Bibcode: 2014SPIE.9147E..5CO
Altcode:
  Incomplete and unstable mode population has long complicated the
  application of optical fiber for transferring star and calibration
  light to high precision spectrographs. The need for improved precision
  calibrators in support of radial velocity planet surveys has led to the
  introduction of coherent wavelengths sources using single mode fibers
  that are then coupled into multi-mode fibers, further exacerbating this
  problem. We explore mode scrambling in annealed optical fiber with and
  without agitation, as compared to that obtained using octagonal fiber
  and using an integrating sphere. We observe improved scrambling with
  annealed fibers compared to conventional and octagonal fibers.

Title: Developments in simulations and software for a near-infrared
    precision radial velocity spectrograph
Authors: Terrien, Ryan C.; Bender, Chad F.; Mahadevan, Suvrath;
   Halverson, Samuel P.; Ramsey, Lawrence W.; Hearty, Frederick R.
Bibcode: 2014SPIE.9152E..26T
Altcode:
  We present developments in simulations and software for the Habitable
  Zone Planet Finder (HPF), an R~50,000 near-infrared cross-dispersed
  radial velocity spectrograph that will be used to search for planets
  around M dwarfs. HPF is fiber-fed, operates in the zYJ bands, and uses
  a 1.7μm cutoff HAWAII-2RG (H2RG) NIR detector. We have constructed an
  end-to-end simulator that accepts as input a range of stellar models
  contaminated with telluric features and processes these through a
  simulated detector. This simulator accounts for the characteristics of
  the H2RG, including interpixel capacitance, persistence, nonlinearities,
  read noise, and other detector characteristics, as measured from our
  engineering-grade H2RG. It also implements realistic order curvature. We
  describe applications of this simulator including optimization of the
  fiber configuration at the spectrograph slit and selection of properties
  for a laser frequency comb calibration source. The simulator has also
  provided test images for development of the HPF survey extraction
  and RV analysis pipeline and we describe progress on this pipeline
  itself, which will implement optimal extraction, laser frequency comb
  and emission lamp wavelength calibration, and cross-correlation based
  RV measurement.

Title: Environmental control system for Habitable-zone Planet Finder
    (HPF)
Authors: Hearty, Fred; Levi, Eric; Nelson, Matt; Mahadevan, Suvrath;
   Burton, Adam; Ramsey, Lawrence; Bender, Chad; Terrien, Ryan; Halverson,
   Samuel; Robertson, Paul; Roy, Arpita; Blank, Basil; Blanchard, Ken;
   Stefansson, Gudmundur
Bibcode: 2014SPIE.9147E..52H
Altcode:
  HPF is an ultra-stable, precision radial velocity near infrared
  spectrograph with a unique environmental control scheme. The
  spectrograph will operate at a mid-range temperature of 180K,
  approximately half way between room temperature and liquid nitrogen
  temperature; it will be stable to sub -milli-Kelvin(mK) levels over a
  calibration cycle and a few mK over months to years. HPF's sensor is a
  1.7 micron H2RG device by Teledyne. The environmental control boundary
  is a 9 m2 thermal enclosure that completely surrounds the optical
  train and produces a near blackbody cavity for all components. A large,
  pressure - stabilized liquid nitrogen tank provides the heat sink for
  the system via thermal straps while a multichannel resistive heater
  control system provides the stabilizing heat source. High efficiency
  multi-layer insulation blanketing provides the outermost boundary of
  the thermal enclosure to largely isolate the environmental system
  from ambient conditions. The cryostat, a stainless steel shell
  derived from the APOGEE design, surrounds the thermal enclosure
  and provides a stable, high quality vacuum environment. The full
  instrument will be housed in a passive 'meat -locker' enclosure to
  add a degree of additional thermal stability and as well as protect
  the instrument. Effectiveness of this approach is being empirically
  demonstrated via long duration scale model testing. The full scale
  cryostat and environmental control system are being constructed for
  a 2016 delivery of the instrument to the Hobby-Eberly Telescope. This
  report describes the configuration of the hardware and the scale-model
  test results as well as projections for performance of the full system.

Title: Deployment of the Hobby-Eberly Telescope wide field upgrade
Authors: Hill, Gary J.; Drory, Niv; Good, John; Lee, Hanshin; Vattiat,
   Brian; Kriel, Herman; Bryant, Randy; Elliot, Linda; Landriau, Martin;
   Leck, Ron; Perry, David; Ramsey, Jason; Savage, Richard; Allen,
   Richard D.; Damm, George; DePoy, D. L.; Fowler, Jim; Gebhardt, Karl;
   Haeuser, Marco; MacQueen, Phillip; Marshall, J. L.; Martin, Jerry;
   Prochaska, Travis; Ramsey, Lawrence W.; Rheault, Jean-Philippe;
   Shetrone, Matthew; Schroeder Mrozinski, Emily; Tuttle, Sarah E.;
   Cornell, Mark E.; Booth, John; Moreira, Walter
Bibcode: 2014SPIE.9145E..06H
Altcode:
  The Hobby-Eberly Telescope (HET) is an innovative large telescope
  located in West Texas at the McDonald Observatory. The HET operates
  with a fixed segmented primary and has a tracker, which moves the
  four-mirror optical corrector and prime focus instrument package to
  track the sidereal and non-sidereal motions of objects. A major upgrade
  of the HET is in progress that will substantially increase the pupil
  size to 10 meters (from 9.2 m) and the field of view to 22 arcminutes
  (from 4 arcminutes) by replacing the corrector, tracker, and prime focus
  instrument package. In addition to supporting existing instruments, and
  a new low resolution spectrograph, this wide field upgrade will feed a
  revolutionary new integral field spectrograph called VIRUS, in support
  of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX§). The
  upgrade is being installed and this paper discusses the current status.

Title: The Habitable-zone Planet Finder: A status update on the
    development of a stabilized fiber-fed near-infrared spectrograph
    for the for the Hobby-Eberly telescope
Authors: Mahadevan, Suvrath; Ramsey, Lawrence W.; Terrien, Ryan;
   Halverson, Samuel; Roy, Arpita; Hearty, Fred; Levi, Eric; Stefansson,
   Gudmundur K.; Robertson, Paul; Bender, Chad; Schwab, Chris; Nelson,
   Matt
Bibcode: 2014SPIE.9147E..1GM
Altcode:
  The Habitable-Zone Planet Finder is a stabilized, fiber-fed, NIR
  spectrograph being built for the 10m Hobby- Eberly telescope (HET) that
  will be capable of discovering low mass planets around M dwarfs. The
  optical design of the HPF is a white pupil spectrograph layout in a
  vacuum cryostat cooled to 180 K. The spectrograph uses gold-coated
  mirrors, a mosaic echelle grating, and a single Teledyne Hawaii-2RG
  (H2RG) NIR detector with a 1.7-micron cutoff covering parts of the
  information rich z, Y and J NIR bands at a spectral resolution of
  R∼50,000. The unique design of the HET requires attention to both
  near and far-field fiber scrambling, which we accomplish with double
  scramblers and octagonal fibers. In this paper we discuss and summarize
  the main requirements and challenges of precision RV measurements in the
  NIR with HPF and how we are overcoming these issues with technology,
  hardware and algorithm developments to achieve high RV precision and
  address stellar activity.

Title: Development of Fiber Fabry-Perot Interferometers as Stable
    Near-infrared Calibration Sources for High Resolution Spectrographs
Authors: Halverson, Samuel; Mahadevan, Suvrath; Ramsey, Lawrence;
   Hearty, Fred; Wilson, John; Holtzman, Jon; Redman, Stephen; Nave,
   Gillian; Nidever, David; Nelson, Matt; Venditti, Nick; Bizyaev,
   Dmitry; Fleming, Scott
Bibcode: 2014PASP..126..445H
Altcode: 2014arXiv1403.6841H
  We discuss the ongoing development of single-mode fiber Fabry-Perot
  (FFP) Interferometers as precise astro-photonic calibration sources for
  high precision radial velocity (RV) spectrographs. FFPs are simple,
  inexpensive, monolithic units that can yield a stable and repeatable
  output spectrum. An FFP is a unique alternative to a traditional etalon,
  as the interferometric cavity is made of single-mode fiber rather
  than an air-gap spacer. This design allows for excellent collimation,
  high spectral finesse, rigid mechanical stability, insensitivity to
  vibrations, and no need for vacuum operation. The device we have tested
  is a commercially available product from Micron Optics. Our development
  path is targeted towards a calibration source for the Habitable-Zone
  Planet Finder (HPF), a near-infrared spectrograph designed to detect
  terrestrial-mass planets around low-mass stars, but this reference could
  also be used in many existing and planned fiber-fed spectrographs as
  we illustrate using the Apache Point Observatory Galactic Evolution
  Experiment (APOGEE) instrument. With precise temperature control
  of the fiber etalon, we achieve a thermal stability of 100 $\mu$K
  and associated velocity uncertainty of 22 cm s$^{-1}$. We achieve a
  precision of $\approx$2 m s$^{-1}$ in a single APOGEE fiber over 12
  hours using this new photonic reference after removal of systematic
  correlations. This high precision (close to the expected photon-limited
  floor) is a testament to both the excellent intrinsic wavelength
  stability of the fiber interferometer and the stability of the APOGEE
  instrument design. Overall instrument velocity precision is 80 cm
  s$^{-1}$ over 12 hours when averaged over all 300 APOGEE fibers and
  after removal of known trends and pressure correlations, implying the
  fiber etalon is intrinsically stable to significantly higher precision.

Title: Suppression of Fiber Modal Noise Induced Radial Velocity
    Errors for Bright Emission-line Calibration Sources
Authors: Mahadevan, Suvrath; Halverson, Samuel; Ramsey, Lawrence;
   Venditti, Nick
Bibcode: 2014ApJ...786...18M
Altcode: 2014arXiv1403.1577M
  Modal noise in optical fibers imposes limits on the signal-to-noise
  ratio (S/N) and velocity precision achievable with the next generation
  of astronomical spectrographs. This is an increasingly pressing problem
  for precision radial velocity spectrographs in the near-infrared (NIR)
  and optical that require both high stability of the observed line
  profiles and high S/N. Many of these spectrographs plan to use highly
  coherent emission-line calibration sources like laser frequency combs
  and Fabry-Perot etalons to achieve precision sufficient to detect
  terrestrial-mass planets. These high-precision calibration sources
  often use single-mode fibers or highly coherent sources. Coupling light
  from single-mode fibers to multi-mode fibers leads to only a very low
  number of modes being excited, thereby exacerbating the modal noise
  measured by the spectrograph. We present a commercial off-the-shelf
  solution that significantly mitigates modal noise at all optical and
  NIR wavelengths, and which can be applied to spectrograph calibration
  systems. Our solution uses an integrating sphere in conjunction with
  a diffuser that is moved rapidly using electrostrictive polymers,
  and is generally superior to most tested forms of mechanical fiber
  agitation. We demonstrate a high level of modal noise reduction with
  a narrow bandwidth 1550 nm laser. Our relatively inexpensive solution
  immediately enables spectrographs to take advantage of the innate
  precision of bright state-of-the art calibration sources by removing
  a major source of systematic noise.

Title: A Y+J Band Laser Frequency Comb for the Habitable Zone
    Planet Finder
Authors: Osterman, Steve; Ycas, G. G.; Diddams, S. A.; Bender, C. F.;
   Donaldson, C. L.; Mahadevan, S.; Quinlan, F.; Ramsey, L. W.
Bibcode: 2013AAS...22114911O
Altcode:
  The Habitable Zone Planet Finder (HPF) scheduled for deployment to the
  Hobby-Eberly Telescope in late 2015 will extend the radial velocity
  search for exoplanets into the near infrared by providing a high
  precision, stabilized near infrared spectrograph spanning the Y+J bands
  (0.98-1.3μm) with 50,000 resolution. Working in the near infrared will
  allow the HPF to study cooler, lower mass stars than is possible with
  the current generation of optical spectrographs. In order to extend the
  precision of the HPF to lower minimum RV signatures we are proposing to
  develop a deployable, fully autonomous version of the Y+J band laser
  frequency comb currently in operation at the NIST Time and Frequency
  Division in Boulder, Colorado. The Y+J comb is derived from the H
  band (1.45-1.7μm) comb which was successfully demonstrated at the
  Hobby-Eberly Telescope in 2010. The deployed version will leverage off
  of existing hardware and demonstrated technology. We present instrument
  architecture and current performance as well as results of long term
  stability tests, filter modeling, modal noise reduction results and
  predicted end-to-end performance.

Title: The UKIRT Planet Finder
Authors: Jones, Hugh R. A.; Barnes, John; Bryson, Ian; Adamson, Andy;
   Henry, David; Montgomery, David; Ives, Derek; Egan, Ian; Lunney,
   David; Rees, Phil; Rayner, John; Ramsey, Larry; Vacca, Bill; Tinney,
   Chris; Liu, Mike
Bibcode: 2013ASSP...37..329J
Altcode:
  We present a conceptual design for the UKIRT Planet Finder (UPF). It is
  a fibre-fed high resolving power (R ∼ 70,000 at 2.5 pixel sampling)
  cryogenic echelle spectrograph operating in the near infrared (0.95-1.8
  μm) and is designed to provide 1 m/s radial velocity measurements. We
  identify the various error sources to overcome in order to achieve
  the required stability. We have constructed models simulating likely
  candidates and demonstrated the ability to recover exoplanetary
  radial-velocity (RV) signals in the infrared. UPF should achieve a
  total RV error of around 1 m/s on a typical M6V star. We use these
  results as an input to a simulated 5-year survey of nearby M stars,
  which has the sensitivity to detect of the order of 30 terrestrial
  mass planets in the habitable zone around those stars. UPF will thus
  test theoretical planet formation models, which predict an abundance
  of terrestrial-mass planets around low-mass stars enabling critical
  tests of planet-formation theories and allowing the identification of
  nearby planets with conditions potentially suitable for life.

Title: A Large Sample of Magnetically-Active Stars Observed With
    Kepler
Authors: Wells, Mark; Neff, J. E.; Brown, A.; Ayres, T. R.; Basri,
   G. S.; Berdyugina, S.; Harper, G.; Hawley, S. L.; Korhonen, H.;
   Kowalski, A.; Micela, G.; Piskunov, N. E.; Ramsey, L. W.; Saar, S. H.;
   Walkowicz, L. M.
Bibcode: 2013AAS...22135415W
Altcode:
  We have observed about 325 stars in our Kepler Guest Observer
  programs (Cycles 1 through 4). For most of these targets, we are
  analyzing extremely high-precision light curves that have been
  continuously sampled every 30 minutes for up to 3 years. Our sample
  of candidate magnetically-active stars was selected primarily using
  GALEX colors. Starspots, pulsations, and variations due to eclipsing
  and contact binaries combine to produce a rich variety of light
  curves. We have developed semi-automated procedures to characterize
  this variability and thus to classify the targets and identify the
  physical mechanisms that dominate their Kepler light curves. We will
  describe these procedures and discuss the range of physical properties
  covered by our final classification scheme. We are using this Kepler
  database of variability over timescales of minutes to years to provide
  diagnostics of flares, starspot formation, evolution, migration, and
  ultimately of stellar cycles in general. This work contains results
  obtained using the NASA Kepler satellite and from the Apache Point
  Observatory, the MMT (using NOAO community access time), and the
  Hobby-Eberly Telescope. Funding is provided by NASA Kepler grants
  NNX10AC51G, NNX11AC79G, and NNX12AC85G to the University of Colorado,
  by NSF grant AST-1109695 to the College of Charleston, and by a grant
  from the South Carolina Space Grant consortium.

Title: Stellar Variability And External Noise Sources With The Kepler
Mission: Can Stellar Cycle Changes Be Revealed?
Authors: Ramsey, Lawrence
Bibcode: 2013adap.prop...39R
Altcode:
  We will provide exploration of stellar and instrument noise properties
  associated with Kepler Mission data to inform exoplanet detection
  capabilities, reveal levels of stellar activity in the Kepler sample
  relative to the Sun, and provide a foundation to determine if Kepler
  data will support stellar cycle quantifications. Gilliland et al
  (2011) provided a study separating observed variations in Kepler time
  series into instrumental and stellar components, taking advantage of
  the unique way in which the same stars are cycled through different
  detectors. The latter study concluded the instrument was noisier
  by a small margin on time scales of transits, while the stars were
  nearly a factor of two more variable on this few hour time scale
  than expected prior to launch. That study used data from the first
  six quarters of Kepler observations; this study will extend the same
  results by over two additional years (through Quarter 15), and utilize
  the latest, updated data products. A more powerful study of intrinsic
  stellar variability can focus on longer (activity) time scales; we
  will provide such a study in an attempt to resolve a controversy on
  variability of the Kepler stars relative to the Sun. Last, but far from
  least, in terms of simple signal-to-noise arguments, data from Kepler
  should easily reveal stellar cycle variations to well below the 0.1%
  amplitude seen for the Sun. However, many instrumental drifts and
  systematics have amplitudes well above the multi-year signal levels
  expected. We will use Kepler's quietest stars to assess prospects for
  extensive stellar cycle studies. The goal of this latter effort is
  to perform all necessary calibrations to demonstrate that Kepler is
  capable of quantifying stellar cycle variations, or, failing this,
  to provide a clear explication of remaining problems that need to
  be overcome. Elucidation of cyclic behavior for thousands of stars
  would (if feasible) be a future seminal achievement for the Kepler
  Mission. This will be a one year program. Actual science on stellar
  cycles would benefit immensely from the longer time series that may
  be avilable in future proposals. The budget is primarily for research
  support of Gilliland -- Science PI on this program -- who will lead
  all phases of the research.

Title: Young Star Populations in the Kepler Field
Authors: Brown, Alexander; Neff, J. E.; Wells, M.; Saar, S.; Furesz,
   G.; Walkowicz, L. M.; Ayres, T. R.; Basri, G. S.; Berdyugina, S.;
   Harper, G.; Hawley, S. L.; Korhonen, H.; Kowalski, A.; Micela, G.;
   Piskunov, N. E.; Ramsey, L. W.
Bibcode: 2013AAS...22135414B
Altcode:
  The Kepler satellite is providing spectacular optical photometric
  light-curves of unprecedented precision and duration that routinely
  allow detailed studies of stellar magnetic activity on late-type stars
  that were difficult previously. Kepler provides multi-year duration
  light-curves that allow investigation of how activity phenomena --
  such as the growth, migration, and decay of star-spots, differential
  rotation, activity cycles, and flaring -- operate on a wide variety of
  single and binary stars. The 105 square degree Kepler Field contains
  tens of thousands of late-type stars showing rotational modulation due
  to star-spots with periods ranging from one day to a ``solar-like''
  month. Short rotation periods and high levels of magnetic activity are
  strongly correlated. However, there are only two basic reasons why stars
  with rotation periods of a few days possess such high angular momentum
  --- either they are close binaries or they are young stars. During
  Kepler GO Cycles 1 through 4 we have been studying the Long-cadence
  (30 minute sampling) photometry of hundreds of active late-type stars
  and as an absolutely essential complement we have been obtaining high
  resolution optical spectra to understand the physical properties of
  these stars. We present results from a spectroscopic survey using the
  MMT Hectochelle multi-object echelle of 4 square degrees of the Kepler
  Field. We have discovered a significant population of young stars with
  Li I absorption indicating ages of ~100 Myr or less at a spatial density
  of at least 20 stars per square degree. Our detected young star sample
  comprises at least 80 stars and represents a dramatic advance compared
  to the previously known sample over the full Kepler Field of three
  stars in this age range. Roughly one sixth of the stars observed are
  young and a similar number short-period binaries based on 2-4 radial
  velocities. We show how the rotational properties of the stars and their
  physical properties are related. This work is based on data obtained
  with the NASA Kepler satellite and the MMT Hectochelle spectrograph
  using NOAO community access time. Support by NASA Kepler grants to the
  University of Colorado and by NSF grant to the College of Charleston.

Title: The Metallicity of the CM Draconis System
Authors: Terrien, Ryan C.; Fleming, Scott W.; Mahadevan, Suvrath;
   Deshpande, Rohit; Feiden, Gregory A.; Bender, Chad F.; Ramsey,
   Lawrence W.
Bibcode: 2012ApJ...760L...9T
Altcode: 2012arXiv1210.4736T
  The CM Draconis system comprises two eclipsing mid-M dwarfs of nearly
  equal mass in a 1.27 day orbit. This well-studied eclipsing binary
  has often been used for benchmark tests of stellar models, since its
  components are among the lowest mass stars with well-measured masses
  and radii (lsim 1% relative precision). However, as with many other
  low-mass stars, non-magnetic models have been unable to match the
  observed radii and effective temperatures for CM Dra at the 5%-10%
  level. To date, the uncertain metallicity of the system has complicated
  comparison of theoretical isochrones with observations. In this Letter,
  we use data from the SpeX instrument on the NASA Infrared Telescope
  Facility to measure the metallicity of the system during primary and
  secondary eclipses, as well as out of eclipse, based on an empirical
  metallicity calibration in the H and K near-infrared (NIR) bands. We
  derive an [Fe/H] = -0.30 ± 0.12 that is consistent across all orbital
  phases. The determination of [Fe/H] for this system constrains a
  key dimension of parameter space when attempting to reconcile model
  isochrone predictions and observations.

Title: Development of a New, Precise Near-infrared Doppler Wavelength
Reference: A Fiber Fabry-Perot Interferometer
Authors: Halverson, Samuel; Mahadevan, Suvrath; Ramsey, Lawrence;
   Redman, Stephen; Nave, Gillian; Wilson, John C.; Hearty, Fred;
   Holtzman, Jon
Bibcode: 2012arXiv1209.2704H
Altcode:
  We present the ongoing development of a commercially available Micron
  Optics fiber-Fabry Perot Interferometer as a precise, stable, easy to
  use, and economic spectrograph reference with the goal of achieving
  &lt;1 m/s long term stability. Fiber Fabry-Perot interferometers (FFP)
  create interference patterns by combining light traversing different
  delay paths. The interference creates a rich spectrum of narrow
  emission lines, ideal for use as a precise Doppler reference. This
  fully photonic reference could easily be installed in existing NIR
  spectrographs, turning high resolution fiber-fed spectrographs into
  precise Doppler velocimeters. First light results on the Sloan Digital
  Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution
  Experiment (APOGEE) spectrograph and several tests of major support
  instruments are also presented. These instruments include a SuperK
  Photonics fiber supercontinuum laser source and precise temperature
  controller. A high resolution spectrum obtained using the NIST 2-m
  Fourier transform spectrometer (FTS) is also presented. We find
  our current temperature control precision of the FFP to be 0.15 mK,
  corresponding to a theoretical velocity stability of 35 cm/s due to
  temperature variations of the interferometer cavity.

Title: Current status of the Hobby-Eberly Telescope wide field upgrade
Authors: Hill, Gary J.; Booth, John A.; Cornell, Mark E.; Good,
   John M.; Gebhardt, Karl; Kriel, Herman J.; Lee, Hanshin; Leck, Ron;
   Moreira, Walter; MacQueen, Phillip J.; Perry, Dave M.; Rafal, Marc D.;
   Rafferty, Tom H.; Ramiller, Chuck; Savage, Richard D.; Taylor, Charles
   A.; Vattiat, Brian L.; Ramsey, Lawrence W.; Beno, Joseph H.; Beets,
   Timothy A.; Esguerra, Jorge D.; Häuser, Marco; Hayes, Richard J.;
   Heisler, James T.; Soukup, Ian M.; Zierer, Joseph J.; Worthington,
   Michael S.; Mollison, Nicholas T.; Wardell, Douglas R.; Wedeking,
   Gregory A.
Bibcode: 2012SPIE.8444E..0KH
Altcode:
  The Hobby-Eberly Telescope (HET) is an innovative large telescope of
  9.2 meter aperture, located in West Texas at the McDonald Observatory
  (MDO). The HET operates with a fixed segmented primary and has a tracker
  which moves the four-mirror corrector and prime focus instrument package
  to track the sidereal and non-sidereal motions of objects. A major
  upgrade of the HET is in progress that will increase the pupil size
  to 10 meters and the field of view to 22' by replacing the corrector,
  tracker and prime focus instrument package. In addition to supporting
  the existing suite of instruments, this wide field upgrade will feed a
  revolutionary new integral field spectrograph called VIRUS, in support
  of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEXχ). This
  paper discusses the current status of this upgrade.

Title: Near-infrared calibration systems for precise radial-velocity
    measurements
Authors: Redman, Stephen L.; Kerber, Florian; Nave, Gillian; Mahadevan,
   Suvrath; Ramsey, Lawrence W.; Smoker, Jonathan; Käufl, Hans-Ulrich;
   Figueira, P. R. L.
Bibcode: 2012SPIE.8446E..8GR
Altcode:
  We present work done to prepare two new near-infrared
  calibration sources for use on high-precision astrophysical
  spectrographs. Uranium-neon is an atomic calibration source,
  commercially available as a hollow-cathode lamp, with over 10 000 known
  emission lines between 0.85 and 4 μm. Four gas cells — containing
  C<SUB>2</SUB>H<SUB>2</SUB>, H<SUP>13</SUP>CN, <SUP>12</SUP>CO, and
  <SUP>13</SUP>CO, respectively—are available as National Institute of
  Standards and Technology (nist) Standard Reference Materials (SRMs),
  and provide narrow absorption lines between 1.5 and 1.65 μm. These
  calibration sources may prove useful for wavelength-calibrating the
  future near-infrared high-precision radial-velocity spectrometers,
  including the Calar Alto high-Resolution search for M dwarfs
  with Exo-earths with a Near-infrared Echelle Spectrograph
  (CARMENES),<SUP>1</SUP> the SpectroPolarimetre InfraROUge
  (SPIRou)<SUP>∗</SUP>, and the Habitable-Zone Planet Finder
  (HPF).<SUP>2</SUP>

Title: The habitable-zone planet finder: a stabilized fiber-fed NIR
    spectrograph for the Hobby-Eberly Telescope
Authors: Mahadevan, Suvrath; Ramsey, Lawrence; Bender, Chad; Terrien,
   Ryan; Wright, Jason T.; Halverson, Sam; Hearty, Fred; Nelson, Matt;
   Burton, Adam; Redman, Stephen; Osterman, Steven; Diddams, Scott;
   Kasting, James; Endl, Michael; Deshpande, Rohit
Bibcode: 2012SPIE.8446E..1SM
Altcode: 2012arXiv1209.1686M
  We present the scientific motivation and conceptual design for the
  recently funded Habitable-zone Planet Finder (HPF), a stabilized
  fiber-fed near-infrared (NIR) spectrograph for the 10 meter class
  Hobby-Eberly Telescope (HET) that will be capable of discovering low
  mass planets around M dwarfs. The HPF will cover the NIR Y and J bands
  to enable precise radial velocities to be obtained on mid M dwarfs,
  and enable the detection of low mass planets around these stars. The
  conceptual design is comprised of a cryostat cooled to 200K, a dual
  fiber-feed with a science and calibration fiber, a gold coated mosaic
  echelle grating, and a Teledyne Hawaii-2RG (H2RG) *NIR detector with
  a 1.7μm cutoff. A uranium-neon hollow-cathode lamp is the baseline
  wavelength calibration source, and we are actively testing laser
  frequency combs to enable even higher radial velocity precision. We
  will present the overall instrument system design and integration
  with the HET, and discuss major system challenges, key choices, and
  ongoing research and development projects to mitigate risk. We also
  discuss the ongoing process of target selection for the HPF survey.

Title: A near-infrared frequency comb for Y+J band astronomical
    spectroscopy
Authors: Osterman, Steve; Ycas, Gabriel G.; Diddams, Scott A.; Quinlan,
   Franklyn; Mahadevan, Suvrath; Ramsey, Lawrence; Bender, Chad F.;
   Terrien, Ryan; Botzer, Brandon; Sigurdsson, Steinn; Redman, Stephen L.
Bibcode: 2012SPIE.8450E..1IO
Altcode: 2012arXiv1209.3295O
  Radial velocity (RV) surveys supported by high precision wavelength
  references (notably ThAr lamps and I2 cells) have successfully
  identified hundreds of exoplanets; however, as the search for
  exoplanets moves to cooler, lower mass stars, the optimum wave band
  for observation for these objects moves into the near infrared (NIR)
  and new wavelength standards are required. To address this need we
  are following up our successful deployment of an H band(1.45-1.7μm)
  laser frequency comb based wavelength reference with a comb working
  in the Y and J bands (0.98-1.3μm). This comb will be optimized for
  use with a 50,000 resolution NIR spectrograph such as the Penn State
  Habitable Zone Planet Finder. We present design and performance details
  of the current Y+J band comb.

Title: Optical fiber modal noise in the 0.8 to 1.5 micron region and
    implications for near infrared precision radial velocity measurements
Authors: McCoy, Keegan S.; Ramsey, Lawrence; Mahadevan, Suvrath;
   Halverson, Samuel; Redman, Stephen L.
Bibcode: 2012SPIE.8446E..8JM
Altcode: 2012arXiv1209.2906M
  Modal noise in fibers has been shown to limit the signal-to-noise
  ratio achievable in fiber-coupled, high-resolution spectrographs
  if it is not mitigated via modal scrambling techniques. Modal noise
  become significantly more important as the wavelength increases and
  presents a risk to the new generation of near-infrared precision
  radial spectrographs under construction or being proposed to search
  for planets around cool M-dwarf stars, which emit most of their light
  in the NIR. We present experimental results of tests at Penn State
  University characterizing modal noise in the far visible out to 1.5
  microns and the degree of modal scrambling we obtained using mechanical
  scramblers. These efforts are part of a risk mitigation effort for the
  Habitable Zone Planet Finder spectrograph currently under development
  at Penn State University.

Title: The SDSS-HET Survey of Kepler Eclipsing Binaries: Spectroscopic
    Dynamical Masses of the Kepler-16 Circumbinary Planet Hosts
Authors: Bender, Chad F.; Mahadevan, Suvrath; Deshpande, Rohit; Wright,
   Jason T.; Roy, Arpita; Terrien, Ryan C.; Sigurdsson, Steinn; Ramsey,
   Lawrence W.; Schneider, Donald P.; Fleming, Scott W.
Bibcode: 2012ApJ...751L..31B
Altcode: 2012arXiv1205.0259B
  We have used high-resolution spectroscopy to observe the Kepler-16
  eclipsing binary as a double-lined system and measure precise radial
  velocities for both stellar components. These velocities yield a
  dynamical mass ratio of q = 0.2994 ± 0.0031. When combined with the
  inclination, i = 90fdg3401<SUP>+0.0016</SUP> <SUB>- 0.0019</SUB>,
  measured from the Kepler photometric data by Doyle et al. (D11), we
  derive dynamical masses for the Kepler-16 components of M<SUB>A</SUB>
  = 0.654 ± 0.017 M <SUB>⊙</SUB> and M<SUB>B</SUB> = 0.1959 ± 0.0031
  M <SUB>⊙</SUB>, a precision of 2.5% and 1.5%, respectively. Our
  results confirm at the ~2% level the mass-ratio derived by D11 with
  their photometric-dynamical model (PDM), q = 0.2937 ± 0.0006. These
  are among the most precise spectroscopic dynamical masses ever measured
  for low-mass stars and provide an important direct test of the results
  from the PDM technique. <P />Based on observations obtained with the
  Hobby-Eberly Telescope, which is a joint project of the University of
  Texas at Austin, the Pennsylvania State University, Stanford University,
  Ludwig-Maximilians-Universität München, and Georg-August-Universität
  Göttingen.

Title: A High-resolution Atlas of Uranium-Neon in the H Band
Authors: Redman, Stephen L.; Ycas, Gabriel G.; Terrien, Ryan;
   Mahadevan, Suvrath; Ramsey, Lawrence W.; Bender, Chad F.; Osterman,
   Steven N.; Diddams, Scott A.; Quinlan, Franklyn; Lawler, James E.;
   Nave, Gillian
Bibcode: 2012ApJS..199....2R
Altcode: 2011arXiv1112.1062R
  We present a high-resolution (R ≈ 50,000) atlas of a uranium-neon
  (U/Ne) hollow-cathode spectrum in the H band (1454-1638 nm) for the
  calibration of near-infrared spectrographs. We obtained this U/Ne
  spectrum simultaneously with a laser-frequency comb spectrum, which we
  used to provide a first-order calibration to the U/Ne spectrum. We then
  calibrated the U/Ne spectrum using the recently published uranium line
  list of Redman et al., which is derived from high-resolution Fourier
  transform spectrometer measurements. These two independent calibrations
  allowed us to easily identify emission lines in the hollow-cathode
  lamp that do not correspond to known (classified) lines of either
  uranium or neon, and to compare the achievable precision of each
  source. Our frequency comb precision was limited by modal noise and
  detector effects, while the U/Ne precision was limited primarily by
  the signal-to-noise ratio (S/N) of the observed emission lines and our
  ability to model blended lines. The standard deviation in the dispersion
  solution residuals from the S/N-limited U/Ne hollow-cathode lamp was 50%
  larger than the standard deviation of the dispersion solution residuals
  from the modal-noise-limited laser-frequency comb. We advocate the use
  of U/Ne lamps for precision calibration of near-infrared spectrographs,
  and this H-band atlas makes these lamps significantly easier to use
  for wavelength calibration.

Title: An H-band Spectroscopic Metallicity Calibration for M Dwarfs
Authors: Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.;
   Deshpande, Rohit; Ramsey, Lawrence W.; Bochanski, John J.
Bibcode: 2012ApJ...747L..38T
Altcode: 2012arXiv1202.1800T
  We present an empirical near-infrared (NIR) spectroscopic method
  for estimating M dwarf metallicities, based on features in the H
  band, as well as an implementation of a similar published method
  in the K band. We obtained R ~ 2000 NIR spectra of a sample of M
  dwarfs using the NASA IRTF-SpeX spectrograph, including 22 M dwarf
  metallicity calibration targets that have FGK companions with known
  metallicities. The H-band and K-band calibrations provide equivalent
  fits to the metallicities of these binaries, with an accuracy of
  ±0.12 dex. We derive the first empirically calibrated spectroscopic
  metallicity estimate for the giant planet-hosting M dwarf GJ 317,
  confirming its supersolar metallicity. Combining this result with
  observations of eight other M dwarf planet hosts, we find that M
  dwarfs with giant planets are preferentially metal-rich compared to
  those that host less massive planets. Our H-band calibration relies
  on strongly metallicity-dependent features in the H band, which will
  be useful in compositional studies using mid- to high-resolution NIR
  M dwarf spectra, such as those produced by multiplexed surveys like
  SDSS-III APOGEE. These results will also be immediately useful for
  ongoing spectroscopic surveys of M dwarfs.

Title: Demonstration of on-sky calibration of astronomical spectra
    using a 25 GHz near-IR laser frequency comb
Authors: Ycas, Gabriel G.; Quinlan, Franklyn; Diddams, Scott A.;
   Osterman, Steve; Mahadevan, Suvrath; Redman, Stephen; Terrien, Ryan;
   Ramsey, Lawrence; Bender, Chad F.; Botzer, Brandon; Sigurdsson, Steinn
Bibcode: 2012OExpr..20.6631Y
Altcode: 2012arXiv1201.5125Y
  We describe and characterize a 25 GHz laser frequency comb based on
  a cavity-filtered erbium fiber mode-locked laser. The comb provides a
  uniform array of optical frequencies spanning 1450 nm to 1700 nm, and
  is stabilized by use of a global positioning system referenced atomic
  clock. This comb was deployed at the 9.2 m Hobby-Eberly telescope at the
  McDonald Observatory where it was used as a radial velocity calibration
  source for the fiber-fed Pathfinder near-infrared spectrograph. Stellar
  targets were observed in three echelle orders over four nights, and
  radial velocity precision of \sim10 m/s (\sim6 MHz) was achieved from
  the comb-calibrated spectra.

Title: Precision Rvs In The Nir: First On-sky Velocities With A U/ne
    Lamp And A Laser Frequency Comb
Authors: Mahadevan, Suvrath; Ramsey, L.; Redman, S.; Bender, C.;
   Terrien, R.; Roy, A.; Botzer, B.; Osterman, S.; Diddams, S.; Ycas,
   G.; Quinlan, F.
Bibcode: 2011ESS.....2.0206M
Altcode:
  Precision radial velocities in the near infrared (NIR) can help
  detect terrestrial mass planets around mid and late M dwarfs that are
  typically too faint in the optical for effective monitoring. The NIR
  poses a new set of calibration and technology challenges. We will
  discuss the current state of the art in NIR spectroscopy, and RV
  precision and present ongoing work at Penn State with the Pathfinder
  NIR testbed. With the Pathfinder we have demonstrated 10-20 m/s radial
  velocity precision in the NIR Y band at the 9m Hobby Eberly telescope
  using a Uranium-Neon hollow cathode lamp as a simultaneous wavelength
  reference. We shall present these results and also new velocity
  results from recent first on-sky observations with an H band laser
  frequency comb developed at NIST and CASA. The innate stability and
  known frequencies of the comb lines provides an excellent calibrator in
  the H band, but numerous systematics like fiber modal noise, tellurics,
  and detector calibration need to be overcome. We will discuss progress
  made on all these fronts with experiments on the Pathfinder testbed. <P
  />We acknowledge support from NSF, NASA, NAI, NIST, Penn State, and
  the Center for Exoplanets &amp; Habitable Worlds.

Title: Visible and Near-Infrared Properties of Optical Fibers Coupled
    to the Pathfinder High-Resolution NIR Spectrograph
Authors: McCoy, K.; Ramsey, L.
Bibcode: 2011amos.confE..69M
Altcode:
  The Penn State Astronomy and Astrophysics Department’s Pathfinder
  instrument is a fiber-fed, warm-bench echelle spectrograph designed
  to explore technical issues that must be resolved in order to measure
  precise radial velocities that will allow the detection of exoplanets
  in the near-infrared (NIR). In May 2010, Pathfinder demonstrated 10-20
  m/s radial-velocity precision in the NIR at the 9 meter Hobby-Eberly
  Telescope. To attain even higher precision, we are investigating the NIR
  properties of the optical fibers that transmit light from the telescope
  to Pathfinder. We conducted a series of modal noise tests with visible
  and NIR laser diodes on a 200 micron diameter, fused-silica, multimode
  optical fiber as the preliminary step in analyzing the degrading
  effects of modal noise on radial-velocity precision. We report these
  test results and comment on our future tests to reduce the negative
  effects of modal noise and focal ratio degradation (FRD). The lessons
  learned from this research and the Pathfinder prototype will be used in
  Pathfinder II, which will aim to achieve better than 5 m/s in the NIR.

Title: Laser Frequency Comb Supported Stellar Radial Velocity
Determination in the NIR: Initial Results.
Authors: Osterman, Steve; Diddams, S.; Quinlan, F.; Ycas, G.;
   Mahadevan, S.; Ramsey, L.; Bender, C.; Terrien, R.; Botzer, B.;
   Redman, S.
Bibcode: 2011ESS.....2.0205O
Altcode:
  The laser frequency comb presents the potential for a revolutionary
  increase in radial velocity precision by providing a calibration
  reference of unprecedented quality in terms of wavelength knowledge,
  repeatability, number, density and regularity of lines. Promising first
  steps have been taken leading to the derivation of stellar radial
  velocities in the NIR H band, a wavelength range well suited to the
  observation of M dwarfs. These stars, with low mass and low luminosity,
  are the most prevalent class of stars within 10 parsecs and can be
  expected to yield a higher reflex velocity for a terrestrial mass
  planet in the liquid water habitable zone than would be the case with
  a more massive star such as our own. We present the design and both
  laboratory and on-sky performance of an H-band laser frequency comb
  used in conjunction with the Penn State Pathfinder testbed spectrograph
  and discuss lessons learned and plans for follow on testing.

Title: VizieR Online Data Catalog: IR spectrum of Uranium hollow
    cathode lamps (Redman+, 2011)
Authors: Redman, S. L.; Lawler, J. E.; Nave, G.; Ramsey, L. W.;
   Mahadevan, S.
Bibcode: 2011yCat..21950024R
Altcode:
  The observations used for our measurements were made with the 1m Fourier
  transform spectrometer (FTS) on Kitt Peak between 1979 and 2002,
  and are publicly available on the National Solar Observatory (NSO)
  Web site (http://diglib.nso.edu/nso_user.html). <P />(1 data file).

Title: The Infrared Spectrum of Uranium Hollow Cathode Lamps from
850 nm to 4000 nm: Wavenumbers and Line Identifications from Fourier
    Transform Spectra
Authors: Redman, Stephen L.; Lawler, James E.; Nave, Gillian; Ramsey,
   Lawrence W.; Mahadevan, Suvrath
Bibcode: 2011ApJS..195...24R
Altcode: 2011arXiv1107.4091R
  We provide new measurements of wavenumbers and line identifications
  of 10, 100 U I and U II near-infrared (NIR) emission lines between
  2500 cm<SUP>-1</SUP> and 12, 000 cm<SUP>-1</SUP> (4000-850 nm) using
  archival Fourier transform spectrometer spectra from the National Solar
  Observatory. This line list includes isolated uranium lines in the Y,
  J, H, K, and L bands (0.9-1.1 μm, 1.2-1.35 μm, 1.5-1.65 μm, 2.0-2.4
  μm, and 3.0-4.0 μm, respectively), and provides six times as many
  calibration lines as thorium in the NIR spectral range. The line lists
  we provide enable inexpensive, commercially available uranium hollow
  cathode lamps to be used for high-precision wavelength calibration of
  existing and future high-resolution NIR spectrographs.

Title: Kepler Observations of Starspot Evolution, Differential
    Rotation, and Flares on Late-Type Stars
Authors: Brown, Alexander; Korhonen, H.; Berdyugina, S.; Walkowicz,
   L.; Kowalski, A.; Hawley, S.; Neff, J.; Ramsey, L.; Redman, S.; Saar,
   S.; Furesz, G.; Piskunov, N.; Harper, G.; Ayres, T.; Tofany, B.
Bibcode: 2011AAS...21820502B
Altcode: 2011BAAS..43G20502B
  The Kepler satellite is providing spectacular optical photometric
  light-curves of unprecedented precision and duration that
  routinely allow detailed studies of stellar magnetic activity on
  late-type stars that were difficult, if not impossible, to attempt
  previously. Rotational modulation due to starspots is commonly seen
  in the Kepler light-curves of late-type stars, allowing detailed
  study of the surface distribution of their photospheric magnetic
  activity. Kepler is providing multi-year duration light-curves that
  allow us to investigate how activity phenomena -- such as the growth,
  migration, and decay of starspots, differential rotation, activity
  cycles, and flaring -- operate on single and binary stars with a
  wide range of mass and convection zone depth. <P />We present the
  first results from detailed starspot modeling using newly-developed
  light-curve inversion codes for a range of GALEX-selected stars with
  typical rotation periods of a few days, that we have observed as part of
  our 200 target Kepler Cycle 1/2 Guest Observer programs. The physical
  properties of the stars have been measured using high resolution
  optical spectroscopy, which allows the Kepler results to be placed
  within the existing framework of knowledge regarding stellar magnetic
  activity. These results demonstrate the powerful diagnostic capability
  provided by tracking starspot evolution essentially continuously for
  more than 16 months. The starspots are clearly sampling the stellar
  rotation rate at different latitudes, enabling us to measure the
  differential rotation and starspot lifetimes. As would be expected,
  stars with few day rotation show frequent flaring that is easily seen
  as "white-light" flares in Kepler light-curves. We compare the observed
  flare rates and occurrence with the starspot properties. <P />This work
  contains results obtained using the NASA Kepler satellite and from the
  Apache Point Observatory, the MMT (using NOAO community access time),
  and the Hobby-Eberly Telescope. Funding is provided by NASA Kepler
  grants NNX10AC51G and NNX11AC79G.

Title: Precision Radial Velocities in the near-infrared Y and H
    bands with the Penn State Pathfinder Instrument
Authors: Mahadevan, Suvrath; Ramsey, L.; Redman, S.; Bender, C.;
   Botzer, B.; Terrien, R.; Osterman, S.; Diddams, S.; Ycas, G.; Quinlan,
   F.; Roy, A.; Zonak, S.
Bibcode: 2011AAS...21740101M
Altcode: 2011BAAS...4340101M
  Precision radial velocities in the near infrared can help detect
  terrestrial mass planets around mid and late M dwarfs that are
  typically too faint in the optical for effective monitoring. We have
  demonstrated 10-15 m/s radial velocity precision in the NIR Y band with
  our warm-bench fiber-fed Pathfinder instrument at the 9m Hobby Eberly
  telescope, and will present these results as well as discuss results
  from the first on-sky observations with an H band laser frequency
  comb. We will also present the instrumental upgrades and modification
  to Pathfinder that have made high NIR velocity precision possible
  with the use of new calibration sources like Uranium lamps and laser
  combs. The ability to achieve this level of precision with a test bed
  bodes well for a stabilized spectrograph built on these principles,
  and we discuss progress toward this as well as challenges like modal
  noise and telluric absorption correction.

Title: First Stellar Radial Velocities with a Laser Frequency Comb:
    Observations in the NIR H Band
Authors: Osterman, Steve; Diddams, S.; Quinlan, F.; Ycas, G.;
   Mahadevan, S.; Ramsey, L.; Bender, C.; Redman, S.; Terrien, R.;
   Botzer, B.
Bibcode: 2011AAS...21740102O
Altcode: 2011BAAS...4340102O
  Advances in high precision radial velocity spectroscopy have been
  hindered by the lack of suitable wavelength references. This has been
  especially the case in the infrared where until recently radial velocity
  precision has been limited to 50-100m/s, hindering investigations
  such as the search for extrasolar planets orbiting cooler M stars
  at these wavelengths. To redress deficiency this we have developed a
  25GHz laser frequency comb spanning the H band and suitable for use
  with spectrographs with spectral resolution in the range of 40,000 -
  60,000, with RV precision limited by instrument stability and object
  S/N rather than by the lack of a suitable wavelength standard. <P />We
  will present CU/NIST frequency comb performance and results obtained
  using the Pennsylvania State University's Pathfinder Spectrograph on
  the Hobby Eberly Telescope and will discuss lessons learned.

Title: A Precision Radial Velocity Pathfinder Instrument in the H
    Band with a Laser Frequency Comb
Authors: Terrien, Ryan; Mahadevan, S.; Ramsey, L.; Bender, C.; Redman,
   S.; Osterman, S.; Diddams, S.; Ycas, G.; Quinlan, F.; Botzer, B.
Bibcode: 2011AAS...21725309T
Altcode: 2011BAAS...4325309T
  We describe changes to the warm-bench, fiber-fed, Penn State Pathfinder
  instrument that enabled us to test the ability to recover precision
  radial velocities in the H-band. The use of thermal blocking filters
  that cut off at 1.7 microns allows us to observe in the H-band by
  blocking the overwhelming thermal flux beyond 2 microns. A PK-50 window
  provides further suppression of this thermal flux. We also describe the
  observations, reduction, and results from an August 2010 test run of
  this instrument with a 25 GHz NIST laser frequency comb calibration
  system. We obtained radial velocities of several bright stars with
  on-sky observation with the laser comb. Our results demonstrate the
  potential of our testbed configuration for obtaining precision radial
  velocities in the NIR, as well as the utility of laser frequency combs
  as wavelength calibrators in this wavelength regime.

Title: The Habitable Zone Planet Finder Project: A Proposed High
    Resolution NIR Spectrograph for the Hobby Eberly Telescope (HET)
    to Discover Low Mass Exoplanets around M Stars
Authors: Mahadevan, S.; Ramsey, L.; Redman, S.; Zonak, S.; Wright,
   J.; Wolszczan, A.; Endl, M.; Zhao, B.
Bibcode: 2010ASPC..430..272M
Altcode:
  Radial velocity precision in the NIR is now approaching the level
  necessary to detect exoplanets around mid-late M stars that are very
  faint in the optical and emit most of their flux in the NIR. The
  Penn State Pathfinder prototype instrument has already demonstrated
  7-10 ms<SUP>-1</SUP> precision on sunlight, and similar precision
  has been reported at the Pathways conference using CRIRES and an
  ammonia gas-cell. We discuss the science goals that motivate a stable
  cross-dispersed, high-resolution NIR spectrograph on a large telescope,
  as well as the path leading from the Pathfinder prototype to one
  such possible instrument—the fiber-fed Habitable Zone Planet Finder
  (HZPF) on the Hobby Eberly Telescope (HET). We also discuss wavelength
  calibration issues specific to the NIR, and our ongoing exploration
  with Pathfinder to mitigate these issues.

Title: Uranium-Neon as a Near-Infrared Calibration Source
Authors: Redman, Stephen; Nave, Gillian; Lawler, Jim; Ramsey, Larry;
   Mahadevan, Suvrath
Bibcode: 2010aepr.confP..17R
Altcode:
  No abstract at ADS

Title: Optical Fibers in Spectrograph Design; A Technical Overview
Authors: Ramsey, Larry
Bibcode: 2010aepr.confE..28R
Altcode: 2010aepr.confE...1R
  No abstract at ADS

Title: The habitable zone planet finder: a proposed high-resolution
    NIR spectrograph for the Hobby Eberly Telescope to discover low-mass
    exoplanets around M dwarfs
Authors: Mahadevan, Suvrath; Ramsey, Larry; Wright, Jason; Endl,
   Michael; Redman, Stephen; Bender, Chad; Roy, Arpita; Zonak, Stephanie;
   Troupe, Nathaniel; Engel, Leland; Sigurdsson, Steinn; Wolszczan,
   Alex; Zhao, Bo
Bibcode: 2010SPIE.7735E..6XM
Altcode: 2010arXiv1007.3235M; 2010SPIE.7735E.227M
  The Habitable Zone Planet Finder (HZPF) is a proposed instrument
  for the 10m class Hobby Eberly telescope that will be capable of
  discovering low mass planets around M dwarfs. HZPF will be fiber-fed,
  provide a spectral resolution R~ 50,000 and cover the wavelength
  range 0.9-1.65μm, the Y, J and H NIR bands where most of the flux is
  emitted by midlate type M stars, and where most of the radial velocity
  information is concentrated. Enclosed in a chilled vacuum vessel with
  active temperature control, fiber scrambling and mechanical agitation,
  HZPF is designed to achieve a radial velocity precision &lt; 3m/s, with
  a desire to obtain &lt;1m/s for the brightest targets. This instrument
  will enable a study of the properties of low mass planets around M
  dwarfs; discover planets in the habitable zones around these stars,
  as well serve as an essential radial velocity confirmation tool for
  astrometric and transit detections around late M dwarfs. Radial velocity
  observation in the near-infrared (NIR) will also enable a search for
  close in planets around young active stars, complementing the search
  space enabled by upcoming high-contrast imaging instruments like GPI,
  SPHERE and PALM3K. Tests with a prototype Pathfinder instrument have
  already demonstrated the ability to recover radial velocities at 7-10
  m/s precision from integrated sunlight and ~15-20 m/s precision on
  stellar observations at the HET. These tests have also demonstrated
  the ability to work in the NIR Y and J bands with an un-cooled
  instrument. We will also discuss lessons learned about calibration and
  performance from our tests and how they impact the overall design of
  the HZPF.

Title: The Pathfinder testbed: exploring techniques for achieving
    precision radial velocities in the near infrared
Authors: Ramsey, Larry W.; Mahadevan, Suvrath; Redman, Stephen;
   Bender, Chad; Roy, Arpita; Zonak, Stephanie; Sigurdsson, Steinn;
   Wolszczan, Alex
Bibcode: 2010SPIE.7735E..71R
Altcode: 2010arXiv1009.0477R; 2010SPIE.7735E.231R
  The Penn State Pathfinder is a prototype warm fiber-fed Echelle
  spectrograph with a Hawaii-1 NIR detector that has already demonstrated
  7-10 m/s radial velocity precision on integrated sunlight. The
  Pathfinder testbed was initially setup for the Gemini PRVS design study
  to enable a systematic exploration of the challenges of achieving
  high radial velocity precision in the near-infrared, as well as to
  test possible solutions to these calibration challenges. The current
  version of the Pathfinder has an R3 echelle grating, and delivers a
  resolution of R~50,000 in the Y, J or H bands of the spectrum. We will
  discuss the on sky-performance of the Pathfinder during an engineering
  test run at the Hobby Eberly Telescope as well the results of velocity
  observations of M dwarfs. We will also discuss the unique calibration
  techniques we have explored, like Uranium-Neon hollow cathode lamps,
  notch filter, and modal noise mitigation to enable high precision
  radial velocity observation in the NIR. The Pathfinder is a prototype
  testbed precursor of a cooled high-resolution NIR spectrograph capable
  of high radial velocity precision and of finding low mass planets
  around mid-late M dwarfs.

Title: The Lunar Orbiter Laser Altimeter Investigation on the Lunar
    Reconnaissance Orbiter Mission
Authors: Smith, David E.; Zuber, Maria T.; Jackson, Glenn B.;
   Cavanaugh, John F.; Neumann, Gregory A.; Riris, Haris; Sun, Xiaoli;
   Zellar, Ronald S.; Coltharp, Craig; Connelly, Joseph; Katz, Richard B.;
   Kleyner, Igor; Liiva, Peter; Matuszeski, Adam; Mazarico, Erwan M.;
   McGarry, Jan F.; Novo-Gradac, Anne-Marie; Ott, Melanie N.; Peters,
   Carlton; Ramos-Izquierdo, Luis A.; Ramsey, Lawrence; Rowlands, David
   D.; Schmidt, Stephen; Scott, V. Stanley; Shaw, George B.; Smith,
   James C.; Swinski, Joseph-Paul; Torrence, Mark H.; Unger, Glenn; Yu,
   Anthony W.; Zagwodzki, Thomas W.
Bibcode: 2010SSRv..150..209S
Altcode:
  The Lunar Orbiter Laser Altimeter (LOLA) is an instrument on the
  payload of NASA’s Lunar Reconnaissance Orbiter spacecraft (LRO)
  (Chin et al., in Space Sci. Rev. 129:391-419, 2007). The instrument
  is designed to measure the shape of the Moon by measuring precisely
  the range from the spacecraft to the lunar surface, and incorporating
  precision orbit determination of LRO, referencing surface ranges to
  the Moon’s center of mass. LOLA has 5 beams and operates at 28 Hz,
  with a nominal accuracy of 10 cm. Its primary objective is to produce
  a global geodetic grid for the Moon to which all other observations
  can be precisely referenced.

Title: Extending the Search for Other Earths with Precision Radial
    Velocity Measurements in the Near-IR
Authors: Redman, Stephen L.; Ramsey, L.; Mahadevan, S.
Bibcode: 2010AAS...21534804R
Altcode: 2010BAAS...42..530R
  M dwarfs, the most common type of star in the Solar neighborhood,
  exhibit higher Doppler radial velocities when orbited by a
  terrestrial mass planet than F, G, K dwarfs since they have lower
  mass. Unfortunately, late M dwarfs have low optical luminosities,
  emitting most of their flux in the near-infrared (NIR). The ExoPlanet
  Task Force has recommended that NIR RV instruments be made a high
  priority. We have been developing such an instrument at Penn State
  and preliminary results for our "pathfinder" instrument have been
  published in PASP (120:870, 2008, p. 887). These studies have been
  extended with a significant upgrade which includes better optimized
  gratings and a substantially improved calibration system. We present
  recent results from Y- and J-band observations in the near-Infrared
  using the Earth's rotational velocity with respect to the Sun as a
  test signal and a Hawaii-1K array. We use these results, along with
  a high resolution spectrum of Barnard's Star (M4) at red limit of the
  CCD to estimate the achievable precision when we move the pathfinder
  to the Hobby-Eberly telescope in the Spring of 2010.

Title: The Habitable Zone Planet Finder: A Proposed High Resolution
    Nir Spectrograph For The Het To Discover Low Mass Exoplanets Around
    M Stars
Authors: Mahadevan, Suvrath; Ramsey, L.; Wolszczan, A.; Wright, J.;
   Endl, M.; Redman, S.
Bibcode: 2010AAS...21542123M
Altcode: 2010BAAS...42..290M
  The Habitable Zone Planet Finder (HZPF) is a proposed instrument for
  the 9m Hobby Eberly telescope that will be capable of discovering
  low mass planets around M dwarfs. HZPF will be fiber-fed, provide a
  spectral resolution R 50,000 and cover the wavelength range 0.9-1.65mm,
  the Y, J and H near infrared (NIR) bands where most of the flux is
  emitted by late type M stars, and where most of the radial velocity
  information is concentrated. Enclosed in a vacuum tank with active
  temperature control, fiber scrambling and mechanical agitation, HZPF
  is designed to achieve a radial velocity precision &lt; 3m/s, with a
  desire to achieve 1m/s for the brightest targets. This instrument will
  enable a study of the properties of low mass planets around M dwarfs;
  discover planets in the habitable zones around these stars, and serve
  as an essential radial velocity confirmation tool for astrometric and
  transit detections around late M dwarfs. Radial velocity observation the
  NIR will also enable a search for close in planets around young active
  stars, complementing the search space enabled by upcoming high-contrast
  imaging instruments. Tests with our laboratory prototype have already
  demonstrated the ability to recover radial velocities in the NIR at
  7-10 m/s precision from integrated sunlight. We will discuss lessons
  learned about calibration and NIR array performance from our tests
  and how they impact the design of the HZPF.

Title: Rotational Velocities for M Dwarfs
Authors: Jenkins, J. S.; Ramsey, L. W.; Jones, H. R. A.; Pavlenko,
   Y.; Gallardo, J.; Barnes, J. R.; Pinfield, D. J.
Bibcode: 2009ApJ...704..975J
Altcode: 2009arXiv0908.4092J
  We present spectroscopic rotation velocities (v sin i) for 56 M dwarf
  stars using high-resolution Hobby-Eberly Telescope High Resolution
  Spectrograph red spectroscopy. In addition, we have also determined
  photometric effective temperatures, masses, and metallicities ([Fe/H])
  for some stars observed here and in the literature where we could
  acquire accurate parallax measurements and relevant photometry. We
  have increased the number of known v sin i values for mid M stars
  by around 80% and can confirm a weakly increasing rotation velocity
  with decreasing effective temperature. Our sample of v sin is peak
  at low velocities (~3 km s<SUP>-1</SUP>). We find a change in the
  rotational velocity distribution between early M and late M stars,
  which is likely due to the changing field topology between partially
  and fully convective stars. There is also a possible further change
  in the rotational distribution toward the late M dwarfs where dust
  begins to play a role in the stellar atmospheres. We also link v
  sin i to age and show how it can be used to provide mid-M star age
  limits. When all literature velocities for M dwarfs are added to our
  sample, there are 198 with v sin i &lt;= 10 km s<SUP>-1</SUP> and 124
  in the mid-to-late M star regime (M3.0-M9.5) where measuring precision
  optical radial velocities is difficult. In addition, we also search
  the spectra for any significant Hα emission or absorption. Forty three
  percent were found to exhibit such emission and could represent young,
  active objects with high levels of radial-velocity noise. We acquired
  two epochs of spectra for the star GJ1253 spread by almost one month
  and the Hα profile changed from showing no clear signs of emission,
  to exhibiting a clear emission peak. Four stars in our sample appear
  to be low-mass binaries (GJ1080, GJ3129, Gl802, and LHS3080), with
  both GJ3129 and Gl802 exhibiting double Hα emission features. The
  tables presented here will aid any future M star planet search target
  selection to extract stars with low v sin i. <P />Based on observations
  obtained with the Hobby-Eberly Telescope, which is a joint project of
  the University of Texas at Austin, the Pennsylvania State University,
  Stanford University, Ludwig-Maximilians-Universität München, and
  Georg-August-Universität Göttingen.

Title: Precision Radial Velocities in the Infrared
Authors: Jones, Hugh R. A.; Rayer, John; Ramsey, Larry; Dent, Bill;
   Longmore, Andy; Vacca, Bill; Liu, Mike; Webster, Adrian; Wolscznan,
   Alex; Barnes, John
Bibcode: 2009ASSP....9..415J
Altcode: 2009svlt.conf..415J
  Over 250 extra-solar planets have been discovered to date using a
  variety of techniques. The majority have been discovered at optical
  wavelengths from the Doppler shift of F, G and K stars induced by
  orbiting planets. We have constructed models simulating likely planets
  around M dwarfs and demonstrated the ability to recover their radial
  velocity signals in the infrared. We have conducted experiments in the
  infrared with a brass-board instrument to explore real-world issues. We
  are thus confident that a stabilised radial velocity spectrometer with
  a single-shot 1 and 1.7 microns coverage at a resolution of around 70
  k can achieve an instrumental radial velocity error of 0.5 m/s. This
  enables the efficient measurement of radial velocities for M, L and
  T spectral classes.

Title: A Pathfinder Instrument for Precision Radial Velocities in
    the Near-Infrared
Authors: Ramsey, L. W.; Barnes, J.; Redman, S. L.; Jones, H. R. A.;
   Wolszczan, A.; Bongiorno, S.; Engel, L.; Jenkins, J.
Bibcode: 2008PASP..120..887R
Altcode: 2008arXiv0806.3749R
  We have designed and tested an in-plane echelle spectrograph configured
  to investigate precision radial velocities from ground-based
  near-infrared observations. The spectrograph operates across the
  spectral range of 0.9-1.7 μm at a spectral resolution of R = 50,000,
  and uses a liquid nitrogen-cooled HAWAII 1 K detector. Repeated
  measurements of the Earth’s rotation via integrated sunlight with
  two different instrument arrangements in the near-infrared Y band
  have produced radial velocities with ∼10 m s<SUP>-1</SUP> rms over
  a period of several hours. The most recent instrument configuration
  has achieved an unbinned rms of 7 m s<SUP>-1</SUP> and suggests that
  infrared radial velocity precisions may be able to approach those
  achieved at optical wavelengths.

Title: Precision radial velocity spectrograph
Authors: Jones, Hugh R. A.; Rayner, John; Ramsey, Larry; Henry,
   David; Dent, Bill; Montgomery, David; Vick, Andy; Ives, Derek; Egan,
   Ian; Lunney, David; Rees, Phil, II; Webster, Adrian; Tinney, Chris;
   Liu, Mike
Bibcode: 2008SPIE.7014E..0YJ
Altcode: 2008SPIE.7014E..31J
  We present a conceptual design for a Precision Radial Velocity
  Spectrograph (PRVS) for the Gemini telescope. PRVS is a fibre fed high
  resolving power (R~70,000 at 2.5 pixel sampling) cryogenic echelle
  spectrograph operating in the near infrared (0.95 - 1.8 microns) and is
  designed to provide 1 m/s radial velocity measurements. We identify the
  various error sources to overcome in order to the required stability. We
  have constructed models simulating likely candidates and demonstrated
  the ability to recover exoplanetary RV signals in the infrared. PRVS
  should achieve a total RV error of around 1 m/s on a typical M6V
  star. We use these results as an input to a simulated 5-year survey of
  nearby M stars. Based on a scaling of optical results, such a survey
  has the sensitivity to detect several terrestrial mass planets in the
  habitable zone around nearby stars. PRVS will thus test theoretical
  planet formation models, which predict an abundance of terrestrial-mass
  planets around low-mass stars.We have conducted limited experiments
  with a brass-board instrument on the Sun in the infrared to explore
  real-world issues achieving better than 10 m/s precision in single
  10 s exposures and better than 5 m/s when integrated across a minute
  of observing.

Title: The image quality of the Southern African Large Telescope
    (SALT)
Authors: O'Donoghue, Darragh E.; Atad-Ettedgui, Eli; Balona, Luis;
   Bigelow, Bruce C.; Booth, John A.; Botha, Lucian; Brink, Janus D.;
   Buckley, David A. H.; Charles, Phil; Christians, Alrin; Clemens,
   J. Christopher; Crause, Lisa A.; Crawford, Steven M.; Evans, Geoffrey
   P.; Gajjar, Hitesh; Hashimoto, Yas; Hendricks, Malcolm; Kniazev,
   Alexei; Koeslag, Anthony R.; Koorts, Willie P.; Kriel, Herman J.;
   Loaring, Nicola S.; Love, Jonathan; Marang, Fred; Metcalfe, Douglas;
   Meyer, Brennan; O'Connor, James; du Plessis, Charl A.; Ramsey,
   Lawrence W.; Romero-Colmenero, Encarni; Sass, Craig; Scholtz, Johann
   C.; Sefako, Ramotholo; Siyengo, Sandisa; Still, Martin; Strydom,
   Ockert J.; Swat, Arkadiusz; Du Toit, Johann F.; Vaisanen, Petri;
   Wells, Martyn; Worters, Hannah
Bibcode: 2008SPIE.7018E..13O
Altcode: 2008SPIE.7018E..32O
  Construction of the Southern African Large Telescope (SALT) was largely
  completed by the end of 2005 and since then it has been in intensive
  commissioning. This has now almost been completed except for the
  telescope's image quality which shows optical aberrations, chiefly
  a focus gradient across the focal plane, along with astigmatism and
  other less significant aberrations. This paper describes the optical
  systems engineering investigation that has been conducted since early
  2006 to diagnose the problem. A rigorous approach has been followed
  which has entailed breaking down the system into the major sub-systems
  and subjecting them to testing on an individual basis. Significant
  progress has been achieved with many components of the optical system
  shown to be operating correctly. The fault has been isolated to a
  major optical sub-system. We present the results obtained so far,
  and discuss what remains to be done.

Title: Warm Planets Around Cool Stars: Searches for Habitable Zone
    Planets Around Late M Dwarfs
Authors: Ramsey, L.; Wolszczan, A.; Bongiorno, S.; Redman, S.; Engel,
   L.; Barnes, J.; Jones, H. R. A.
Bibcode: 2008ASPC..398..505R
Altcode:
  The low mass of M stars, less than 0.5 solar masses, combined with
  close in orbits yield radial velocity amplitudes for planets in
  the habitable zone around these stars that are well within current
  limits of 1-2 m/s achieved with visible-light instruments. These
  same instruments become significantly challenged when looking at
  M5 dwarfs and cooler. However, if one takes advantage of the fact
  that M-stars emit most of their energy in the near-infrared (NIR),
  hundreds of targets become accessible to 8-meter class telescopes
  with instruments such as the Precision Radial Velocity Spectrometer
  (PRVS) for Gemini. We present some preliminary laboratory results that
  demonstrate the viability and challenges of PRV work in the NIR.

Title: The PRVS Pathfinder
Authors: Ramsey, Lawrence W.; Redman, S.; Wolszczan, A.; Jones, H.;
   Barnes, J.
Bibcode: 2007AAS...211.1118R
Altcode: 2007BAAS...39..747R
  The Precision Radial Velocity Spectrometer (PRVS) is a fiber coupled
  near infrared (NIR) spectrometer being designed for the Gemini
  International Observatory specifically to search for planets around
  M stars. These stars emit most of their flux at wavelengths between 1
  and 2 microns. These low mass stars are the most likely place where PRV
  techniques will allow detection of earth mass planets in the so called
  "Habitable Zone". The pathfinder instrument has become a significant
  tool in mitigating design, performance and cost risks for the PRVS. Last
  year we demonstrated the ability to detect radial velocity variations
  at the 10-15 meter/sec level. Since then, we have made significant
  progress in our understanding of the limitations of the PRVS in the
  NIR. In particular, we present the latest improvements we have made to
  the calibration spectra, as well as the characterization and suppression
  of the modal noise in the optical fibers.

Title: Precision Radial Velocity Spectrometer
Authors: Jones, Hugh; Rayner, J.; Ramsey, L.; Barnes, J.; Vacca, B.;
   Tinney, C.; Liu, M.; Dent, B.; Wolszczan, A.; Webster, A.
Bibcode: 2007AAS...211.1701J
Altcode: 2007BAAS...39Q.767J
  The Precision Radial Velocity Spectrometer (PRVS) is a 1.0-1.8 micron
  R 70,000 second-generation Gemini instrument design resulting from
  the Aspen Process. It is designed to deliver short- and long- term
  stability of better than 1 m/s. We have constructed models simulating
  likely candidates and demonstrated the ability to recover exoplanetary
  radial velocity signals in the infrared. In addition we have conducted
  limited experiments with a brass-board instrument to explore real-world
  issues yielding precisions of better than 10 m/s. The mass-sensitivity
  of the Doppler technique around low-mass primaries means that PRVS
  will be sensitive to terrestrial-mass planets orbiting in the habitable
  zone of M dwarfs. While the design of PRVS is driven by the stability
  necessary to achieve long-term precise radial velocity measurements,
  as a cross-dispersed infrared spectrograph with a large wavelength
  coverage and high dispersion which is always available PRVS should
  also be important for a wide range of other science, e.g., gamma-ray
  burst follow-up. PRVS is intended to be fully commissioned in 2011.

Title: M-dwarf Target Selection for our PRVS Planet Search Project
Authors: Jenkins, James; Jones, H. R. A.; Ramsey, L.
Bibcode: 2007AAS...211.1702J
Altcode: 2007BAAS...39R.767J
  PRVS is a precision radial-velocity spectrometer that aims to attain
  1m/s precision in the near-IR. It is scheduled to be added to the Gemini
  suite of instruments by 2011. Therefore, we are currently preparing
  a number of precursor programs to fully exploit the science that PRVS
  will provide. One of the main aims of PRVS will be discovering planets
  around cool substellar objects. Therefore, we have selected a candidate
  list of cool stars that will provide ideal targets for PRVS. We firstly
  have selected a number of bright M-dwarfs and measured their rotation
  velocity (v sin i) using HRS on the HET. A deconvolution technique
  was used to generate high S/N line profiles using a cool atmosphere
  line list from the VALD database. The slowest rotators will be the
  high priority targets for our PRVS planet search project since they
  will provide the lowest noise thresholds and best sensitivity. I will
  discuss both the methodology and initial results from this work and
  then explain where the project will lead in the future.

Title: A Planetary-Mass Companion to the K0 Giant HD 17092
Authors: Niedzielski, A.; Konacki, M.; Wolszczan, A.; Nowak, G.;
   Maciejewski, G.; Gelino, C. R.; Shao, M.; Shetrone, M.; Ramsey, L. W.
Bibcode: 2007ApJ...669.1354N
Altcode: 2007arXiv0705.0935N
  We report the discovery of a substellar-mass companion to the K0
  giant HD 17092 with the Hobby-Eberly Telescope. In the absence
  of any correlation of the observed 360 day periodicity with the
  standard indicators of stellar activity, the observed radial velocity
  variations are most plausibly explained in terms of a Keplerian
  motion of a planetary-mass body around the star. As the estimated
  stellar mass is 2.3 M<SUB>solar</SUB>, the minimum mass of the planet
  is 4.6 M<SUB>J</SUB>. The planet's orbit is characterized by a mild
  eccentricity of e=0.17 and a semimajor axis of 1.3 AU. This is the
  tenth published detection of a planetary companion around a red giant
  star. Such discoveries add to our understanding of planet formation
  around intermediate-mass stars, and they provide dynamical information
  on the evolution of planetary systems around post-main-sequence stars.

Title: Development of A Protype Infrared Exoplanet Tracker for All
    Sky Extrasolar Planet Survey
Authors: Guo, Pengcheng; Ge, J.; Mahadevan, S.; Ramsey, L.
Bibcode: 2006AAS...209.8513G
Altcode: 2006BAAS...38.1016G
  We present a design of a prototype infrared version of the Exoplanet
  Tracker (ET). This instrument is a combination of a fixed-delay
  interferometer with a medium resolution near infrared spectrograph
  (R 10,000). It inherits the design of the single object optical ET
  instrument at the Kitt Peak 2.1m telescope, which has been used for
  high precision radial velocity observations since 2004, including
  a discovery of ET-1(HD102195b) planet. This IR ET is optimized for
  high throughput and Doppler precision in 0.9-1.8 microns. An existing
  medium resolution spectrograph available at Penn State will be used for
  initial lab testing and telescope demonstration. We will also present
  instrument performance simulation results. <P />Once the capability is
  demonstrated, we will develop a multiple object version for the Sloan
  2.5m telescope for surveying nearby tens of thousands of M dwarfs for
  new planets during All Sky Extrasolar Planet Survey.

Title: Exploring Precision Radial Velocities in the NIR: PRVS
    Pathfinder
Authors: Ramsey, Lawrence W.; Bongiorno, S.; Engel, L.; Redman, S.;
   Wolszczan, A.; Jones, H. R.; Barnes, J.
Bibcode: 2006AAS...209.8514R
Altcode: 2006BAAS...38.1016R
  In summer of 2005 we began a program at Penn State to build a test
  instrument to explore issues involved with attaining 1 meter/sec
  Precision Radial Velocities (PRV) in the near infrared where M and L
  stars emit most of their flux. These low mass stars are the most likely
  place where PRV techniques will allow detection of earth mass planets in
  the “Habitable Zone”. Key issues studied are calibration techniques,
  effects of telluric absorption and modal noise in fibers. The instrument
  is a standard in-plane echelle spectrograph with a LN2 cooled Hawaii
  1K array. It can be set to cover selected regions between 1.0 and 1.7
  microns. More recently our experiments were aimed more directly toward
  addressing key issues in the design approach to the Gemini Precision
  Radial Velocity Spectrometer (PRVS) taken by the UK ATC/Penn State/U
  Hawaii/U Hertfordshire team. Tests to date have focused on measuring the
  earth’s rotation signature in the integrated sunlight spectrum. We
  present results showing 10 meter/sec or better precision and compare
  the observed errors with what is expected from the information content
  of the solar spectrum in this region.

Title: The First Extrasolar Planet Discovered with a New-Generation
    High-Throughput Doppler Instrument
Authors: Ge, Jian; van Eyken, Julian; Mahadevan, Suvrath; DeWitt,
   Curtis; Kane, Stephen R.; Cohen, Roger; Vanden Heuvel, Andrew; Fleming,
   Scott W.; Guo, Pengcheng; Henry, Gregory W.; Schneider, Donald P.;
   Ramsey, Lawrence W.; Wittenmyer, Robert A.; Endl, Michael; Cochran,
   William D.; Ford, Eric B.; Martín, Eduardo L.; Israelian, Garik;
   Valenti, Jeff; Montes, David
Bibcode: 2006ApJ...648..683G
Altcode: 2006astro.ph..5247G
  We report the detection of the first extrasolar planet, ET-1 (HD
  102195b), using the Exoplanet Tracker (ET), a new-generation Doppler
  instrument. The planet orbits HD 102195, a young star with solar
  metallicity that may be part of the local association. The planet
  imparts radial velocity variability to the star with a semiamplitude of
  63.4+/-2.0 m s<SUP>-1</SUP> and a period of 4.11 days. The planetary
  minimum mass (msini) is 0.488M<SUB>J</SUB>+/-0.015M<SUB>J</SUB>. The
  planet was initially detected in the spring of 2005 with the Kitt
  Peak National Observatory (KPNO) 0.9 m coudé feed telescope. The
  detection was confirmed by radial velocity observations with the ET
  at the KPNO 2.1 m telescope and also at the 9 m Hobby-Eberly Telescope
  (HET) with its High Resolution Spectrograph. This planetary discovery
  with a 0.9 m telescope around a V=8.05 magnitude star was made possible
  by the high throughput of the instrument: 49% measured from the fiber
  output to the detector. The ET's interferometer-based approach is an
  effective method for planet detection. In addition, the ET concept
  is adaptable to multiple-object Doppler observations or very high
  precision observations with a cross-dispersed echelle spectrograph to
  separate stellar fringes over a broad wavelength band. In addition
  to spectroscopic observations of HD 102195, we obtained brightness
  measurements with one of the automated photometric telescopes at
  Fairborn Observatory. Those observations reveal that HD 102195 is a
  spotted variable star with an amplitude of ~0.015 mag and a 12.3+/-0.3
  day period. This is consistent with spectroscopically observed Ca II H
  and K emission levels and line-broadening measurements but inconsistent
  with rotational modulation of surface activity as the cause of the
  radial velocity variability. Our photometric observations rule out
  transits of the planetary companion.

Title: Contamination control of space-based laser instruments
Authors: Chen, Philip; Hedgeland, Randy; Ramsey, Larry; Rivera,
   Rachel; Houston, Karrie
Bibcode: 2006SPIE.6291E..04C
Altcode: 2006SPIE.6291E...4C
  Space based laser missions have gained their popularity in areas
  such as: communication, power beaming, ranging, altimetry, and Light
  Detection and Ranging. The capabilities of 1.0 micron lasers offer
  a host of improvements in the knowledge gaps that exist and help
  promote our understanding of our Earth and lunar environments as well as
  planetary and space science applications. Some past and present National
  Aeronautics and Space Administration missions that have been developed
  for increasing our universal knowledge of such environments and
  applications include: The Shuttle Laser Altimeter, Mars Orbiter Laser
  Altimeter, Geoscience Laser Altimeter System, Mercury Laser Altimeter,
  Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, and
  Lunar Orbiter Laser Altimeter. The effort of contamination control
  depends on the specific performance goals, instrument designs,
  and planned operating scenarios of such missions. Trace amounts
  of contamination have been shown to greatly reduce the performance
  of 1.0 micron space based laser systems. In addition, the type of
  contamination plays an important role in the degree of degradation
  and helps to define the "contamination sensitivity" of the mission. A
  space based laser mission is considered highly contamination sensitive
  and therefore requires an unprecedented contamination control effort.

Title: Stellar Astrophysics on the Hobby-Eberly Telescope
Authors: Ramsey, Lawrence W.
Bibcode: 2005AIPC..752....3R
Altcode:
  We briefly describe the Hobby-Eberly Telescope (HET) and its present
  status and give several examples of successful stellar astrophysics
  programs. The HET was primarily driven by a science mission of
  conducting spectroscopic surveys. In addition the HET's unique design
  derives from considering that telescopes are largely used for exposure
  times of an hour or less at moderate zenith distances and modest image
  quality that is based on median site seeing which is consistent with a
  survey mission. We present results from planet searches, large radial
  velocity surveys, and Sloan Digital Sky Survey follow up programs in
  this context. The queue-scheduled nature of the HET makes it especially
  effective at synoptic programs that require a large aperture.

Title: The Hobby-Eberly Telescope: performance upgrades, status,
    and plans
Authors: Booth, John A.; Adams, Mark T.; Barker, Edwin S.; Bash,
   Frank N.; Fowler, James R.; Good, John M.; Hill, Gary J.; Kelton,
   Philip W.; Lambert, David L.; MacQueen, Phillip J.; Palunas, Povilas;
   Ramsey, Lawrence W.; Wesley, Gordon L.
Bibcode: 2004SPIE.5489..288B
Altcode:
  The Hobby-Eberly Telescope (HET) is a fixed-elevation, 9.2-m telescope
  with a spherical primary mirror and a tracker at prime focus to follow
  astronomical objects. The telescope was constructed for $13.9M over
  the period 1994-1997. A series of extensive engineering upgrades
  and corrective actions have been completed recently, resulting in
  significantly improved delivered image quality and increased operational
  efficiency. The telescope's Spherical Aberration Corrector (SAC) optics
  were recoated with a highly reflective and durable broadband coating at
  Lawrence Livermore National Laboratory. The software mount model that
  maintains optical alignment of the SAC with the 11-m primary mirror
  array was recalibrated and improved. The acquisition and guiding optics
  for both the High Resolution Spectrograph (HRS) and the Low Resolution
  Spectrograph (LRS) were reworked and improved, allowing for better focus
  and SAC alignment monitoring and control. Recoating of the primary
  mirror segment array was begun. Telescope images of 0.82 arcseconds
  have been recorded for sustained periods in preliminary testing
  following the engineering upgrade, an improvement of 50% over previous
  best performance. Additional engineering upgrades are scheduled to
  consolidate these performance gains and to continue improving delivered
  image quality, throughput, and telescope operational efficiency. The
  HET is now capable of the science performance for which it was designed.

Title: Performance of the Hobby-Eberly Telescope and facility
    instruments
Authors: Hill, Gary J.; MacQueen, Phillip J.; Ramsey, Lawrence W.;
   Shetrone, Matthew D.
Bibcode: 2004SPIE.5492...94H
Altcode:
  The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of
  9.2 meter aperture, located in West Texas at McDonald Observatory. The
  HET operates with a fixed segmented primary and has a tracker which
  moves the four-mirror corrector and prime focus instrument package
  to track the sidereal and non-sidereal motions of objects. The HET
  has been taking science data for five years, but the image quality
  and primary mirror stability have been far from specifications. Work
  over the past two years has improved performance significantly, and
  demonstrated site-seeing limited images of 0.8 arcsec., showing that
  the telescope will meet all specifications. The performance of the HET
  is discussed in detail. The first phase of HET instrumentation includes
  three facility instruments: the Low Resolution Spectrograph (LRS), the
  Medium Resolution Spectrograph (MRS), and High Resolution Spectrograph
  (HRS). The current status of the instruments is described. Upcoming
  near infrared capabilities for the LRS and MRS are also discussed.

Title: SparsePak: A Formatted Fiber Field Unit for the WIYN Telescope
    Bench Spectrograph. I. Design, Construction, and Calibration
Authors: Bershady, Matthew A.; Andersen, David R.; Harker, Justin;
   Ramsey, Larry W.; Verheijen, Marc A. W.
Bibcode: 2004PASP..116..565B
Altcode: 2004astro.ph..3456B
  We describe the design and construction of a formatted
  fiber field unit, SparsePak, and characterize its optical and
  astrometric performance. This array is optimized for spectroscopy
  of low surface brightness extended sources in the visible and
  near-infrared. SparsePak contains 82, 4.7" fibers subtending an area
  of 72<SUP>''</SUP>×71<SUP>''</SUP> in the telescope focal plane and
  feeds the WIYN Bench Spectrograph. Together, these instruments are
  capable of achieving spectral resolutions of λ/Δλ~20,000 and an
  area-solid angle product of ~140 arcsec<SUP>2</SUP> m<SUP>2</SUP> per
  fiber. Laboratory measurements of SparsePak lead to several important
  conclusions on the design of fiber termination and cable curvature
  to minimize focal ratio degradation. SparsePak itself has throughput
  above 80% redward of 5200 Å and 90%-92% in the red. Fed at f/6.3, the
  cable delivers an output of 90% encircled energy at nearly f/5.2. This
  has implications for performance gains if the WIYN Bench Spectrograph
  were to have a faster collimator. Our approach to integral-field
  spectroscopy yields an instrument that is simple and inexpensive to
  build, yet yields the highest area-solid angle product per spectrum of
  any system in existence. An Appendix details the fabrication process
  in sufficient detail for others to repeat. SparsePak was funded by the
  National Science Foundation and the University of Wisconsin-Madison
  Graduate School, and is now publicly available on the WIYN Telescope
  through the National Optical Astronomical Observatories.

Title: PW And: a Young, Single, Spotted, and Flare K2-Dwarf
Authors: Montes, D.; López-Santiago, J.; Fernández-Figueroa, M. J.;
   Ramsey, L. W.
Bibcode: 2004IAUS..219..915M
Altcode: 2003IAUS..219E..34M
  The single K2 dwarf PW And (HD 1405) has been studied using high
  resolution echelle spectra taken during eight observing runs from
  1999 to 2002. Accurate radial velocity and rotational velocity have
  been determined by cross correlation with standards stars. The U V W
  velocity components and the age of 30-80 Myr estimated by using the
  color magnitude diagram and the LiI line confirm its membership to the
  young Local Association moving group. We have analysed the photospheric
  activity (starspots) studying the changes in the bisector of the peak
  of the cross correlation function (CCF) which are related to changes
  in the profile of the photospheric lines. The variations of the radial
  velocity up to 2 km/s that we have found are related with the variations
  in the CCF bisectors. The chromospheric activity has been analyzed by
  applying the spectral subtraction technique to the H<SUB>alpha</SUB>
  H<SUB>beta</SUB> NaI D1&amp;D2 HeI D3 MgIb triplet CaII H&amp;K and
  CaII IRT lines. Two flares was detected during the 2001 and 2002
  observing runs. Variations in the activity seem to be related to the
  photospheric ones showing a good correlation between radial velocity
  changes in the CCF bisector and equivalent width of different lines.

Title: Rotational modulation of the photospheric and chromospheric
    activity in the young, single K2-dwarf PW And
Authors: López-Santiago, J.; Montes, D.; Fernández-Figueroa, M. J.;
   Ramsey, L. W.
Bibcode: 2003A&A...411..489L
Altcode: 2003astro.ph..9072L
  High resolution echelle spectra of PW And (HD 1405) have been
  taken during eight observing runs from 1999 to 2002. The detailed
  analysis of the spectra allow us to determine its spectral type
  (K2V), mean heliocentric radial velocity (V<SUB>hel</SUB> = -11.15 km
  s<SUP>-1</SUP>) rotational velocity (vsin i = 22.6 km s<SUP>-1</SUP>),
  and equivalent width of the lithium line lambda 6707.8 Å (EW(Li I)
  = 273 mÅ). The kinematic (Galactic Velocity (U,V,W)) confirms its
  membership in the Local Association moving group, in agreement with
  the age (30 to 80 Myrs) inferred from the color magnitude diagram
  and the lithium equivalent width. Photospheric activity (presence of
  cool spots that disturb the profiles of the photospheric lines) has
  been detected as changes in the bisectors of the cross correlation
  function (CCF) resulting of cross-correlate the spectra of PW And
  with the spectrum of a non-active star of similar spectral type. These
  variations of the CCF bisectors are related to the variations in the
  measured radial velocities and are modulated with a period similar to
  the photometric period of the star. At the same time, chromospheric
  activity has been analyzed, using the spectral subtraction technique
  and simultaneous spectroscopic observations of the Hα , Hβ , Na I
  D<SUB>1</SUB> and D<SUB>2</SUB>, He I D<SUB>3</SUB>, Mg I b triplet,
  Ca II H&amp;K, and Ca II infrared triplet lines. A flare was observed
  during the last observing run of 2001, showing an enhancement in the
  observed chromospheric lines. A less powerful flare was observed on
  2002 August 23. The variations of the chromospheric activity indicators
  seem to be related to the photospheric activity. A correlation between
  radial velocity, changes in the CCF bisectors and equivalent width of
  different chromospheric lines is observed with a different behaviour
  between epochs 1999, 2001 and 2002. <P />Based on observations made
  with the 2.2 m telescope of the German-Spanish Astronomical Centre,
  Calar Alto (Almería, Spain), operated by the Max-Planck-Institute for
  Astronomy, Heidelberg, jointly with the Spanish National Commission
  for Astronomy, with the Nordic Optical Telescope (NOT), operated on
  the island of La Palma jointly by Denmark, Finland, Iceland, Norway
  and Sweden, in the Spanish Observatorio del Roque de Los Muchachos
  of the Instituto de Astrofísica de Canarias, with the Isaac Newton
  Telescope (INT) operated on the island of La Palma by the Isaac Newton
  Group in the Spanish Observatorio del Roque de Los Muchachos of the
  Instituto de Astrofísica de Canarias, with the Italian Telescopio
  Nazionale Galileo (TNG) operated on the island of La Palma by the
  Centro Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica)
  at the Spanish Observatorio del Roque de Los Muchachos of the Instituto
  de Astrofisica de Canarias and with the Hobby-Eberly Telescope (HET)
  operated by McDonald Observatory on behalf of The University of Texas
  at Austin, the Pennsylvania State University, Stanford University,
  Ludwig-Maximilians-Universität München, and Georg-August-Universität
  Göttingen. <P />Tables 1, 3, 4 and Figs. 4, 7, 8, 14, 16, 18, 19,
  21 are only available in electronic form at http://www.edpsciences.org

Title: The Hobby-Eberly Telescope medium resolution spectrograph
    and fiber instrument feed
Authors: Ramsey, Lawrence W.; Engel, Leland G.; Sessions, Nicholas;
   DeFilippo, Christopher; Graver, Michelle; Mader, Jeffery
Bibcode: 2003SPIE.4841.1036R
Altcode:
  The Medium Resolution Spectrograph (MRS) is a versatile, fiber-fed
  echelle spectrograph for the Hobby-Eberly Telescope (HET). This
  instrument is designed for a wide range of scientific investigations
  and includes single-fiber inputs for the study of point-like sources,
  synthetic slits of fibers for long slit spectroscopy 9 independently
  positionable probes for multi-object spectroscopy, and a circular
  fiber integral field unit. The MRS consists of two beams. The visible
  beam has wavelength coverage from 450 - 900 nm in a single exposure
  with resolving power between 5,300 and 20,000 depending on the fibers
  configuration selected. This beam also has capability in the ranges
  380 - 950 nm by altering the angles of the cross-disperser gratings. A
  second beam operating in the near-infrared has coverage of 900 - 1300
  nm with resolving power between 5,300 and 10,000. Both beams can be
  used simultaneously and are fed by the HET Fiber Instrument Feed (FIF)
  which is mounted at the prime focus of the telescope and positions
  the fibers feeding the MRS. The MRS started commissioning summer 2002.

Title: Fiber fed spectral calibration with the Hobby-Eberly telescope
Authors: Tufts, Joseph R.; Hill, Gary J.; Wesley, Gordon L.; MacQueen,
   Phillip J.; Ramsey, Lawrence W.
Bibcode: 2003SPIE.4841.1162T
Altcode:
  The Hobby-Eberly Telescope (HET) imposes unique constraints on
  the design of a spectral calibration system. Its 9.2 m aperture
  and queue scheduled operation make traditional dome screens
  impractical. Furthermore, the changing pupil of the HET's tilted
  Aricebo design is far more drastic than the simple rotation of
  traditional alt-azimuth telescopes. Given these constraints we elected
  to build an internal spectral calibration system (SCS) common to all
  instruments. The SCS can feed all HET instruments from a uniformly
  illuminated Lambertian screen located within the spherical abberation
  corrector (SAC) at the telescope's second pupil. A moving baffle
  installed at the third pupil will reproduce, during calibration, the
  actual HET pupil seen in a science exposure. We eliminated all heat
  sources at the SAC by locating the lamps in the basement below the
  telescope and coupling source to screen through 12 600 μm diameter
  35 m long fibers.

Title: Performance of the facility instruments on the Hobby-Eberly
    telescope
Authors: Hill, Gary J.; MacQueen, Phillip J.; Ramsey, Lawrence W.
Bibcode: 2003SPIE.4841...43H
Altcode:
  The Hobby-Eberly Telescope (HET) is a revolutionary large telescope of
  9.2 meter aperture, located in West Texas at McDonald Observatory. Early
  scientific operations started on October 8, 1999. The HET operates
  with a fixed segmented primary and has a tracker which moves the
  four-mirror corrector and prime focus instrument package to track the
  sidereal and non-sidereal motions of objects. As of two years ago,
  the HET was taking science data but the image quality and primary
  mirror stability were far from specifications. We established the HET
  Completion Project to identify and fix these problems, and here we
  describe the current performance of the HET relative to its goals,
  focusing on progress made in the past two years. The first phase
  of HET instrumentation includes three facility instruments: the Low
  Resolution Spectrograph (LRS) and High Resolution Spectrograph (HRS),
  which are in operation, and the Medium Resolution Spectrograph (MRS),
  which will be commissioned in the summer and autumn. The current status
  of the instruments is described in detail with performance measures.

Title: The Hobby-Eberly Telescope Completion Project
Authors: Booth, John A.; Wolf, Marsha J.; Fowler, James R.; Adams,
   Mark T.; Good, John M.; Kelton, Philip W.; Barker, Edwin S.; Palunas,
   Povilas; Bash, Frank N.; Ramsey, Lawrence W.; Hill, Gary J.; MacQueen,
   Phillip J.; Cornell, Mark E.; Robinson, Edward L.
Bibcode: 2003SPIE.4837..919B
Altcode:
  The Hobby-Eberly Telescope (HET) is a fixed-elevation, 9.2-m telescope
  with a spherical primary mirror and a tracker at prime focus to follow
  astronomical objects. The telescope was constructed for $13.9M over
  the period 1994-1997. A number of telescope performance deficiencies
  were identified and corrected following construction. Remaining
  problems included: 1) Dome seeing, 2) inadequate initial mirror segment
  alignment accuracy, and 3) mirror segment misalignment with time. The
  HET Completion Project was created in May 2001 to attack these problems
  and to identify and solve the next tier of problems. To address
  dome seeing, large louvers were installed and in operation by May
  2002. Efforts are also underway to eliminate or suppress heat sources
  within the dome environment. To address segment alignment accuracy, a
  prototype Shack-Hartmann device, the Mirror Alignment Recovery System
  (MARS), was built and is in routine use at HET. The Segment Alignment
  Maintenance System (SAMS) is in early operation and has markedly
  improved telescope performance. Two Differential Image Motion Monitor
  (DIMM) telescopes were brought into regular operation in July 2001 to
  quantify atmospheric seeing at HET. As these improvements have been
  implemented, telescope image quality has improved significantly. Plans
  are in place to address additional performance issues.

Title: Mirror Alignment Recovery System (MARS) on the Hobby-Eberly
    Telescope
Authors: Wolf, Marsha J.; Palunas, Povilas; Booth, John A.; Ward,
   Michael H.; Wirth, Allan; Wesley, Gordon L.; O'Donoghue, Darragh;
   Ramsey, Lawrence W.
Bibcode: 2003SPIE.4837..714W
Altcode:
  The Mirror Alignment Recovery System (MARS) is a Shack-Hartmann based
  sensor at the center of curvature (CoC) of the Hobby-Eberly Telescope
  (HET) spherical primary mirror used to align the 91 mirror segments. The
  instrument resides in a CoC tower next to the HET dome, a location which
  provides a challenging set of problems including wind shake and seeing
  from two different domes. The system utilizes an internal light source
  to illuminate the HET and a reference mirror to provide focused spot
  locations from a spherical surface. A custom lenslet array is sized
  to the HET pupil image, matching a single hexagonal lenslet to each
  mirror segment. Centroids of the HET mirror segment spots are compared
  to the reference spot locations to measure tip/tilt misalignments of
  each segment. A MARS proof-of-concept (POC) instrument, tested on the
  telescope in 2001, utilized a commercial wavefront sensor from Adaptive
  Optics Associates. The final system uses the same concept, but is
  customized for optimal performance on the HET. MARS replaces previous
  burst-antiburst alignment techniques and provides a more intuitive
  method of aligning the primary mirror for telescope operators. The POC
  instrument has improved median HET stack sizes by 0.3" EE50, measured
  at the CoC tower. The current alignment accuracy is 0.14" rms (0.28"
  rms on the sky), resolution is 0.014", measurement precision is 0.027"
  rms, and segment capture range is +/- 5". With continuing improvements
  in HET dome ventilation and the addition of software customized for
  removal of tower motion during measurement, the alignment accuracy
  is expected to reach approximately 0.04" rms in the final MARS, to be
  installed in late 2002.

Title: Doppler high precision extra-solar planet surveys by a fixed
    delay interferometer
Authors: Ge, Jian; van Eyken, Julian C.; Mahadevan, Suvrath; DeWitt,
   Curtis; Ramsey, Lawrence W.; Shaklan, Stuart B.; Pan, Xiaopei
Bibcode: 2003SPIE.4838..503G
Altcode:
  A fixed delay interferometer combined with a post-disperser is a new
  technique for high precision radial velocity (RV) measurements. The
  Doppler measurements are conducted by monitoring the stellar fringe
  phase shifts of the interferometer instead of absorption line centroid
  shifts as in the echelle. High Doppler sensitivity is achieved through
  optimizing the optical delay in the interferometer and measuring
  multiple fringes over a broadband. The broadband operation is achieved
  by using the post-disperser for dispersing fringes in different
  wavelengths. Comparing to the state-of-the-art cross-dispersed echelle
  spectroscopy, this interferometer technique provides almost identical RV
  precision based on photon statistics. However, the interferometer method
  has a potential for lower systematic noise due to its simpler instrument
  response than the echelle. The interferometer can be optimized for
  higher throughput than the echelle. The interferometer approach also
  allows fringes to be recorded in one dispersion order instead of many
  cross-dispersed echelle orders. Therefore, this instrument opens up a
  great opportunity for multi-object observations to allow all sky surveys
  for extra-solar planets at moderate sized wide field telescopes. Initial
  observations with a prototype at the Hobby-Eberly 9 m and Palomar 5 m
  telescopes demonstrate ~9 m/s Doppler RV precision with stellar fringe
  data recorded on a 1kx1k CCD detector (or 140 Å wavelength coverage),
  a S/N ~ 120 per pixel and a post-disperser spectral resolving power
  of R = 6,700. This precision is consistent with the photon noise
  limit. Future improvement in wavelength coverage and wavelength
  calibration can reduce the Doppler error to a few m/s or less.

Title: L Dwarfs Found in Sloan Digital Sky Survey Commissioning
    Data. II. Hobby-Eberly Telescope Observations
Authors: Schneider, Donald P.; Knapp, Gillian R.; Hawley, Suzanne L.;
   Covey, Kevin R.; Fan, Xiaohui; Ramsey, Lawrence W.; Richards, Gordon
   T.; Strauss, Michael A.; Gunn, James E.; Hill, Gary J.; MacQueen,
   Phillip J.; Adams, Mark T.; Hill, Grant M.; Ivezić, Željko; Lupton,
   Robert H.; Pier, Jeffrey R.; Saxe, David H.; Shetrone, Matthew; Tufts,
   Joseph R.; Wolf, Marsha J.; Brinkmann, J.; Csabai, István; Hennessy,
   G. S.; York, Donald G.
Bibcode: 2002AJ....123..458S
Altcode: 2001astro.ph.10273S
  Low-dispersion optical spectra have been obtained with the Hobby-Eberly
  Telescope of 22 very red objects found in early imaging data from the
  Sloan Digital Sky Survey (SDSS). The objects are assigned spectral types
  on the Two Micron All Sky Survey (2MASS) system and are found to range
  from late M to late L. The red and near-infrared colors from SDSS and
  2MASS correlate closely with each other, and most of the colors are
  closely related to spectral type in this range; the exception is the
  i*-z* color, which appears to be independent of spectral type between
  about M7 and L4. The spectra suggest that this independence is due
  to the disappearance of the TiO and VO absorption in the i band for
  later spectral types, the presence of strong Na I and K I absorption
  in the i band, and the gradual disappearance of the 8400 Å absorption
  of TiO and FeH in the z band. Based on observations obtained with
  the Sloan Digital Sky Survey, which is owned and operated by the
  Astrophysical Research Consortium, and on observations obtained with
  the Hobby-Eberly Telescope, which is a joint project of the University
  of Texas at Austin, Pennsylvania State University, Stanford University,
  Ludwig-Maximillians-Universität München, and Georg-August-Universität
  Göttingen.

Title: Extra-solar Planet Studies with New Instrument Technology at
    Penn State
Authors: Ge, J.; van Eyken, J.; Mahadevan, S.; Debes, J.; McDavitt,
   D.; Bernecker, J.; De Witt, C.; Chakraborty, A.; Berger, D.; Ramsey,
   L.; Shaklan, S.; Pan, X.
Bibcode: 2001AAS...199.3304G
Altcode: 2001BAAS...33.1356G
  Several new instruments have been developed at Penn State for
  studying extra-solar planets around nearby stars. An optical
  dispersed interferometer, a combination of an interferometer and a
  medium resolution (R = 10,000) spectrograph, called Exoplanet Tracker
  (ET), is designed to provide high Doppler precision ( ~ 2 m/s), high
  throughput ( ~20%) measurements of radial velocity. Initial observing
  results from the HET 9m and Palomar 5m telescopes with a prototype will
  be presented. A Penn State near IR Imaging Spectrometer (PIRIS) has
  been used at the Mt. Wilson 100inch telescope with a powerful natural
  guide star adaptive optics system. It has an IR coronagraph mode and
  a special Gaussian pupil mode for providing high contrast imaging
  (10<SUP>4</SUP>) of nearby stars to allow possible detection of faint
  companions and planetary disks within 1-2 arcsec of stars. New observing
  results will be reported. An anamorphic silicon immersion grating with
  80x40 mm<SUP>2</SUP> etched grating area is being developed at Penn
  State Nanofabrication facility using photolithography and anisotropic
  chemical etching techniques and will provide a very high spectral
  resolution at the diffraction limit (R = 200,000 at 2.3 micron and R
  =100,000 at 4.6 micron). This grating will be coupled with existing
  IR instruments such as the Arizona Imager and Echelle Spectrograph
  (ARIES) at large ground-based telescopes to search for protoplanets
  around nearby young stellar objects.

Title: A new Virtual Interferometer technique for Extrasolar Planet
    Searches
Authors: Mahadevan, S.; Ge, J.; van Eyken, J.; DeWitt, C.; Berger,
   D.; Ramsey, L. W.
Bibcode: 2001AAS...199.0302M
Altcode: 2001BAAS...33.1303M
  A new instrument has been designed and developed at Penn State for high
  precision Doppler radial velocity measurements using the Moire fringe
  technique. The Moire fringes generated by superimposing a digital
  comb on two dimensional stellar spectra allow us to translate Doppler
  shifts in the dispersion direction into much larger Moire fringe shifts
  (3-5 times larger) in the slit direction. The magnification of Moire
  fringes and a much simpler phase shift of a sinosoidal pattern enable
  precision Doppler velocity measurements. This prototype instrument
  using a medium resolution spectrograph( R 10,000) can provide much
  higher throughput (5-10 times more) than conventional high resolution
  echelle spectrographs. We have demonstrated velocity measurements in
  the 30 m/s range with this virtual interferometer and further work will
  allow us to improve the accuracy to 5-10 m/s. The Virtual Interferometer
  will fill a niche in the 5-50 m/s range allowing a much deeper survey
  of stellar objects. This can be important in setting constraints on
  SIM grid stars as well as finding companions around fainter stars.

Title: A Moire Fringing Spectrometer for Extra-Solar Planet Searches
Authors: van Eyken, J. C.; Ge, J.; Mahadevan, S.; De Witt, C.; Ramsey,
   L. W.; Berger, D.; Shaklan, S.; Pan, X.
Bibcode: 2001AAS...199.0303V
Altcode: 2001BAAS...33.1303V
  We have developed a prototype moire fringing spectrometer for high
  precision radial velocity measurements for the detection of extra-solar
  planets. This combination of Michelson interferometer and spectrograph
  overlays an interferometer comb on a medium resolution stellar spectrum,
  producing Moire patterns. Small changes in the doppler shift of the
  spectrum lead to corresponding large shifts in the Moire pattern (Moire
  magnification). The sinusoidal shape of the Moire fringes enables
  much simpler measurement of these shifts than in standard echelle
  spectrograph techniques, facilitating high precision measurements with
  a low cost instrument. Current data analysis software we have developed
  has produced short-term repeatability (over a few hours) to 5-10m/s,
  and future planned improvements based on previous experiments should
  reduce this significantly. We plan eventually to carry out large scale
  surveys for low mass companions around other stars. This poster will
  present new results obtained in the lab and at the HET and Palomar 5m
  telescopes, the theory of the instrument, and data analysis techniques.

Title: The Chandra Deep Survey of the Hubble Deep Field-North
    Area. II. Results from the Caltech Faint Field Galaxy Redshift
    Survey Area
Authors: Hornschemeier, A. E.; Brandt, W. N.; Garmire, G. P.;
   Schneider, D. P.; Barger, A. J.; Broos, P. S.; Cowie, L. L.; Townsley,
   L. K.; Bautz, M. W.; Burrows, D. N.; Chartas, G.; Feigelson, E. D.;
   Griffiths, R. E.; Lumb, D.; Nousek, J. A.; Ramsey, L. W.; Sargent,
   W. L. W.
Bibcode: 2001ApJ...554..742H
Altcode: 2001astro.ph..1494H
  A deep X-ray survey of the Hubble Deep Field-North (HDF-N) and its
  environs is performed using data collected by the Advanced CCD Imaging
  Spectrometer (ACIS) on board the Chandra X-Ray Observatory. Currently
  a 221.9 ks exposure is available, the deepest ever presented, and
  here we give results on X-ray sources located in the 8.6‧×8.7‧
  area covered by the Caltech Faint Field Galaxy Redshift Survey (the
  ``Caltech area''). This area has (1) deep photometric coverage in
  several optical and near-infrared bands; (2) extensive coverage at
  radio, submillimeter, and mid-infrared wavelengths; and (3) some of the
  deepest and most complete spectroscopic coverage ever obtained. It is
  also where the X-ray data have the greatest sensitivity; the minimum
  detectable fluxes in the 0.5-2 keV (soft) and 2-8 keV (hard) bands are
  ~1.3×10<SUP>-16</SUP> and ~6.5×10<SUP>-16</SUP> ergs cm<SUP>-2</SUP>
  s<SUP>-1</SUP>, respectively. More than ~80% of the extragalactic X-ray
  background in the hard band is resolved. The 82 Chandra sources detected
  in the Caltech area are correlated with more than 25 multiwavelength
  source catalogs, and the results of these correlations as well as
  spectroscopic follow-up results obtained with the Keck and Hobby-Eberly
  Telescopes are presented. All but nine of the Chandra sources are
  detected optically with R&lt;~26.5. Redshifts are available for 39%
  of the Chandra sources, including 96% of the sources with R&lt;23 the
  redshift range is 0.1-3.5, with most sources having z&lt;1.5. Eight of
  the X-ray sources are located in the HDF-N itself, including two not
  previously reported. A population of X-ray faint, optically bright,
  nearby galaxies emerges at soft-band fluxes of &lt;~3×10<SUP>-16</SUP>
  ergs cm<SUP>-2</SUP> s<SUP>-1</SUP>. Our multiwavelength correlations
  have set the tightest constraints to date on the X-ray emission
  properties of μJy radio sources, mid-infrared sources detected by the
  Infrared Space Observatory (ISO), and very red (R-K<SUB>s</SUB>&gt;5.0)
  objects. A total of 16 of the 67 1.4 GHz μJy sources in the Caltech
  area are detected in the X-ray band, and the detection rates for
  starburst-type and AGN-candidate μJy sources are comparable. Only two
  of the 17 red, optically faint (I&gt;25) μJy sources are detected
  in X-rays. While many of the starburst-type μJy sources appear to
  contain obscured active galactic nuclei (AGNs), the Chandra data are
  consistent with the majority of the μJy radio sources being powered
  by star formation. A total of 11 of the ~100 ISO mid-infrared sources
  found in and near the HDF-N are detected in X-rays. In the HDF-N itself,
  where both the infrared coverage and the X-ray coverage are deepest,
  it is notable that six of the eight Chandra sources are detected by
  ISO; most of these are known to be AGNs where the X-ray and infrared
  detections reveal both the direct and indirect accretion power being
  generated. The high X-ray-to-infrared matching rate bodes well for
  future sensitive infrared observations of faint X-ray sources. Four
  of the 33 very red objects that have been identified in the Caltech
  area are detected in X-rays these four are among our hardest Chandra
  sources, and we argue that they contain moderately luminous obscured
  AGNs. Overall, however, the small Chandra detection fraction suggests a
  relatively small AGN content in the optically selected very red object
  population. A stacking analysis of the very red objects not detected
  individually by Chandra yields a soft-band detection with an average
  soft-band X-ray flux of ~1.9×10<SUP>-17</SUP> ergs cm<SUP>-2</SUP>
  s<SUP>-1</SUP> the observed emission may be associated with the hot
  interstellar media of moderate-redshift elliptical galaxies. Constraints
  on AGN candidates, extended X-ray sources, and Galactic objects in the
  Caltech area are also presented. Based on observations obtained at the
  W. M. Keck Observatory, which is operated jointly by the California
  Institute of Technology and the University of California. Based on
  observations obtained by the Hobby-Eberly Telescope (HET), which is a
  joint project of The University of Texas at Austin, The Pennsylvania
  State University, Stanford University, Ludwig-Maximillians-Universität
  München, and Georg-August-Universität Göttingen.

Title: High-Redshift Quasars Found in Sloan Digital Sky Survey
    Commissioning Data. V. Hobby-Eberly Telescope Observations
Authors: Schneider, Donald P.; Fan, Xiaohui; Strauss, Michael A.; Gunn,
   James E.; Richards, Gordon T.; Hill, Gary J.; MacQueen, Phillip J.;
   Ramsey, Lawrence W.; Adams, Mark T.; Booth, John A.; Hill, Grant M.;
   Knapp, G. R.; Lupton, Robert H.; Saxe, David H.; Shetrone, Matthew;
   Tufts, Joseph R.; Vanden Berk, Daniel E.; Wolf, Marsha J.; York,
   Donald G.; Anderson, John E., Jr.; Anderson, Scott F.; Bahcall,
   Neta A.; Brinkmann, J.; Brunner, Robert; Csabai, István; Fukugita,
   Masataka; Hennessy, G. S.; Ivezić, Željko; Lamb, Donald Q.; Munn,
   Jeffrey A.; Thakar, Aniruddha R.
Bibcode: 2001AJ....121.1232S
Altcode: 2000astro.ph.12083S
  We report the discovery of 27 quasars with redshifts between 3.58 and
  4.49. The objects were identified as high-redshift candidates based
  on their colors in Sloan Digital Sky Survey commissioning data. The
  redshifts were confirmed with low-resolution spectra obtained at the
  Hobby-Eberly Telescope. The quasars' i<SUP>*</SUP> magnitudes range
  from 18.55 to 20.97. Nearly 60% of the quasar candidates observed
  are confirmed spectroscopically as quasars. Two of the objects are
  broad absorption line quasars, and several other quasars appear to
  have narrow associated absorption features. Based on observations
  obtained with the Sloan Digital Sky Survey, which is owned and
  operated by the Astrophysical Research Consortium, and with the
  Hobby-Eberly Telescope, which is a joint project of the University of
  Texas at Austin, Pennsylvania State University, Stanford University,
  Ludwig-Maximillians-Universität München, and Georg-August-Universität
  Göttingen.

Title: The AGN content in the HDF-N and flanking fields as seen
    by Chandra
Authors: Alexander, D. M.; Brandt, W. N.; Hornschemeier, A. E.;
   Garmire, G. P.; Schneider, D. P.; Barger, A. J.; Broos, P. S.; Cowie,
   L. L.; Townsley, L. K.; Bautz, M. W.; Burrows, D. N.; Chartas, G.;
   Feigelson, E. D.; Griffiths, R.; Lumb, D.; Nousek, J. A.; Ramsey,
   L. W.; Sargent, W. L. W.
Bibcode: 2000AAS...197.7402A
Altcode: 2000BAAS...32.1520A
  We present a multi-wavelength analysis of the Chandra study in
  the Hubble Deep Field (HDF) and its environs (the Caltech region)
  obtained using 225 ks of data collected by the Advanced CCD Imaging
  Spectrometer (ACIS). We have detected 82 sources within this region and
  have positionally cross-correlated these sources with multi-wavelength
  source lists. We focus on the possible AGN detections of 5 Chandra
  sources. We argue that one of these sources is a high-redshift QSO II
  candidate object based on its X-ray, optical and infrared colours. The
  other 4 sources are all extremely red objects (EROs, R-K&gt;5) and
  have hard X-ray colours. The possible identification of AGN activity in
  these objects ( ~10% of the EROs in this region) could prove important
  from the viewpoints of understanding the nature of EROs and the nature
  of the hard X-ray background. We acknowledge the financial support of
  NASA grant NAS 8-38252 and the NSF CAREERS grant AST-998 3783.

Title: Development of high quality silicon grisms at Penn State for
    high resolution infrared spectroscopy
Authors: Bernecker, J.; Ge, J.; McDavitt, D.; Hajj, A.; Ramsey, L.;
   Fonash, S.; Horn, M.
Bibcode: 2000AAS...197.1510B
Altcode: 2000BAAS...32.1429B
  We have developed a new chemical etching process using tetramethyl
  ammonium hydroxide (TMAH) instead of the traditional potassium hydroxide
  (KOH) to fabricate silicon gratings taking advantage of Penn State's
  state-of-the-art Nanofabrication Facility supported by the NSF. The
  first set of etched gratings have surface quality comparable to
  the best silicon gratings developed by a team led by Jian Ge at
  Lawrence Livermore National laboratory (LLNL) using the KOH process
  in early 2000. For example, the scattered light level at 0.6238 μ m
  is less than 3%. The great advantage of this new approach is that it
  significantly simplifies the fabrication process of silicon gratings
  on large, thick silicon substrates. This new fabrication technique is
  being applied in the development of silicon grisms one inch in size
  for several near-IR astronomical instruments including the Gemini
  8m telescope IR instruments, the Goddard Space Flight Center (GSFC)
  wide field near-IR multi-object spectrograph, and Steward Observatory
  PISCES near-IR camera and Arizona Imager and Echelle Spectrograph
  (ARIES). Status of the development and performance of the silicon
  grisms are reported. The development of silicon grisms is supported
  by the Penn State Eberly College of Sciences.

Title: Extra-solar planet searches with a Penn State optical/IR
    dispersive interferometer at the Hobby-Eberly Telescope
Authors: McDavitt, D.; Ge, J.; DeWitt, C.; Bernecker, J.; Mellon,
   R.; Mahadevan, S.; Ramsey, L.; Wolszczan, A.; Rushford, M.
Bibcode: 2000AAS...197.1504M
Altcode: 2000BAAS...32.1428M
  An optical/infrared dispersive interferometer is being developed at Penn
  State for extra-solar planet searches at the Hobby-Eberly Telescope
  (HET). This instrument is a combination of a wide angle Michelson
  type interferometer and an intermediate resolution spectrograph (R
  ≈ 15000). It is designed to provide very low instrument noise for
  sensitive Doppler radial velocity measurements aimed at detecting
  extra-solar planets with a velocity perturbation amplitude of a few
  m/s around nearby F, G, K and M dwarfs. It is a modified version of a
  prototype, developed by Jian Ge and his collaborators earlier at LLNL,
  with a much improved detection efficiency to allow observation of faint
  stars (V ≈ 11 mag.) in the both optical and near-IR wavelengths. The
  prototype with R = 5600 has demonstrated a radial velocity precision
  of 7 m/s at the Lick 1 m telescope in 1999. New instrument components
  including an imaging slicer and an interferometer cavity control
  system are being developed and tested at Penn State. The image slicer
  is used to convert the telescope's circular beams to rectangular ones
  in order to increase the detection efficiency and also allow convenient
  placement of an interferometer fringe comb on stellar absorption lines
  for precision fringe phase measurements. The interferometer cavity
  control system is used to reduce systematic errors and also control
  phase shifts. Reference sources other than iodine absorption are
  being studied for calibrating the new instrument at red and near-IR
  wavelengths. The instrument's first light at the HET will be spring
  2001. Simulations of the instrument's performance show that a Doppler
  radial velocity precision of 1 m/s can be achieved for a late type
  star with a S/N of 200, a wavelength coverage of 500 Å at 1.55 μ m
  and R = 15000. The development of the instrument is supported by the
  Penn State Eberly College of Sciences.

Title: The Sources Comprising the X-ray Background in the
    HDF<SUB>N</SUB> Region observed by the Chandra X-ray Observatory
Authors: Garmire, G. P.; Brandt, N. W.; Hornschemeier, A. E.;
   Schneider, D. P.; Broos, P. S.; Townsley, L. K.; Burrows, D. N.;
   Chartas, G.; Feigelson, E. D.; Nousek, J. A.; Ramsey, L. W.; Barger,
   A. J.; Cowie, L. L.; Bautz, M. W.; Griffiths, R.; Lumb, D.; Sargent,
   W. L. W.
Bibcode: 2000AAS...197.7401G
Altcode: 2000BAAS...32R1519G
  The Chandra X-ray Observatory (CXC) has observed the HDF-N region
  (a 17' by 19' area including the HDF-N) for 224.7 ks as of this
  writing. Another 775 ks will be devoted to this region in the next six
  months. A total of about 200 sources have been detected in the 0.5 -
  8.0 keV energy band. The 2.0 - 8.0 keV Log N(&gt;S) vs Log S plot,
  where N is the areal density of sources and S the flux, reveals that the
  bulk of the sky flux comes from sources brighter than 10<SUP>-14</SUP>
  ergs/cm<SUP>2</SUP>/s. The majority of these sources lies closer than
  a redshift of 1, based on 51 redshifts measured thus far. The X-ray
  spectra of the sources show a gradual hardening with decreasing
  source intensity, with the fainter sources (3 x 10<SUP>-15</SUP>
  ergs/cm<SUP>2</SUP>/s in the 0.5 - 10.0 keV band) exhibiting a photon
  number spectral slope of 1.35+/-0.2. This work is supported in part
  by NASA grant NAS 8-38252(GPG PI), NASA GSRP grant NGT5-50247 (AEH),
  NSF CAREER award AST-9983783 and the Alfred P. Sloan Foundation (WNB),
  and NSF grant AST99-00703 (DPS).

Title: Issues in scaling the ELT up to 100 m
Authors: Ray, Frank B.; Bash, Frank N.; Ramsey, Lawrence W.; Sebring,
   Thomas A.
Bibcode: 2000SPIE.4004..405R
Altcode:
  The Hobby-Eberly Telescope (HET) has been examined as a prototype for
  an Extremely Large Telescope (ELT) with a 33- meter diameter primary
  mirror. In this paper we examine the feasibility of scaling the HET/ELT
  up to 100-meters in diameter. In this 100-meter telescope design (called
  ELTX) the advantages of the tilted Arecibo concept seem to emerge even
  more strongly. For example the whole primary mirror is below grade
  and extremely well shielded from wind shake and the Stewart platform
  which carries the spherical aberration corrector and the instruments
  is capable of being scaled up to this massive size without any serious
  problems. Such a design is on track for probable science missions in
  the next half century.

Title: Performance testing of the Hobby-Eberly Telescope primary
    mirror array
Authors: Adams, Mark T.; Booth, John A.; Hill, Grant M.; Ramsey,
   Lawrence W.
Bibcode: 2000SPIE.4004..471A
Altcode:
  To improve the image quality performance of the Hobby-Eberly Telescope's
  (HET) segmented primary mirror and to assist in the requirements
  definition for an optical alignment sensing and control system,
  multiple engineering tests have been designed and executed. The most
  significant of these tests have been the alignment maintenance baseline
  and solid mount tests. Together, these engineering tests defined the
  complex thermal and non-thermal response modes of the steel HET primary
  mirror truss and quantified the performance of the segment support
  system. We discuss the configuration and performance of the HET primary
  mirror, and discuss our engineering test motivation, goals, design,
  implementation and results. We also discuss the implications of our
  primary mirror performance test results for conceptually similar next
  generation telescope designs, such as the Extremely Large Telescope.

Title: Commissioning experience with the 9.2-m Hobby-Eberly Telescope
Authors: Barnes, Thomas G.; Adams, Mark T.; Booth, John A.; Cornell,
   Mark E.; Gaffney, Niall I.; Fowler, James R.; Hill, Gary J.; Hill,
   Grant M.; Nance, Craig E.; Piche, Francois; Ramsey, Lawrence W.;
   Ricklefs, Randall L.; Spiesman, William J.; Worthington, P. T.
Bibcode: 2000SPIE.4004...14B
Altcode:
  The HET is unique among 9-meter class telescopes in featuring an
  Arecibo-like design with a focal surface tracker. The focal surface
  tracker causes image quality and pointing/tracking performance to
  interact in a complex way that has no precedent in astronomical
  telescope system design and that has presented unusual demands upon
  commissioning. The fixed-elevation, segmented primary-mirror array
  offers some simplifications over traditional telescope design in
  principle, but has presented challenges in practice. The sky access
  characteristics of the HET also place unique demands on observational
  planning and discipline. The HET is distinguished by uniquely low
  construction and operating costs which affected commissioning. In this
  contribution, we describe those aspects of our commissioning experience
  that may impact how similar telescopes are designed, especially those
  with larger aperture, and review the challenges and lessons learned from
  commissioning a 9-meter class telescope with a small technical team.

Title: Hobby-Eberly Telescope operations model
Authors: Adams, Mark T.; Barnes, Thomas G.; Nance, Craig E.; Ramsey,
   Lawrence W.
Bibcode: 2000SPIE.4010...16A
Altcode:
  The Hobby-Eberly telescope (HET) is an innovative, low cost 9- meter
  class telescope that specializes in visible and near- infrared, queue
  observing mode spectroscopy. The operations costs for this telescope
  follow the capital cost model, being approximately 15 - 20% that of
  other 9-meter telescopes. In this contribution we describe the HET
  operations model and our early operations and scientific experience with
  this telescope, emphasizing those aspects that most directly impact
  the scientific productivity of the HET and describing the actions we
  have taken to optimize the telescope's scientific return.

Title: The Missing Link: Early Methane (``T'') Dwarfs in the Sloan
    Digital Sky Survey
Authors: Leggett, S. K.; Geballe, T. R.; Fan, Xiaohui; Schneider,
   Donald P.; Gunn, James E.; Lupton, Robert H.; Knapp, G. R.; Strauss,
   Michael A.; McDaniel, Alex; Golimowski, David A.; Henry, Todd J.;
   Peng, Eric; Tsvetanov, Zlatan I.; Uomoto, Alan; Zheng, Wei; Hill,
   G. J.; Ramsey, L. W.; Anderson, Scott F.; Annis, James A.; Bahcall,
   Neta A.; Brinkmann, J.; Chen, Bing; Csabai, István; Fukugita,
   Masataka; Hennessy, G. S.; Hindsley, Robert B.; Ivezić, Željko;
   Lamb, D. Q.; Munn, Jeffrey A.; Pier, Jeffrey R.; Schlegel, David J.;
   Smith, J. Allyn; Stoughton, Chris; Thakar, A. R.; York, Donald G.
Bibcode: 2000ApJ...536L..35L
Altcode: 2000astro.ph..4408L
  We report the discovery of three cool brown dwarfs that fall in
  the effective temperature gap between the latest L dwarfs currently
  known, with no methane absorption bands in the 1-2.5 μm range, and
  the previously known methane (T) dwarfs, whose spectra are dominated
  by methane and water. The newly discovered objects were detected as
  very red objects in the Sloan Digital Sky Survey imaging data and
  have JHK colors between the red L dwarfs and the blue Gl 229B-like
  T dwarfs. They show both CO and CH<SUB>4</SUB> absorption in their
  near-infrared spectra in addition to H<SUB>2</SUB>O, with weaker
  CH<SUB>4</SUB> absorption features in the H and K bands than those
  in all other methane dwarfs reported to date. Due to the presence of
  CH<SUB>4</SUB> in these bands, we propose that these objects are early
  T dwarfs. The three form part of the brown dwarf spectral sequence and
  fill in the large gap in the overall spectral sequence from the hottest
  main-sequence stars to the coolest methane dwarfs currently known.

Title: Early science results from the Hobby-Eberly telescope
Authors: Hill, Gary J.; MacQueen, Phillip J.; Ramsey, Lawrence W.;
   Robinson, Edward L.
Bibcode: 2000SPIE.4005..240H
Altcode:
  We present science results from the first four months of early
  operations of the Hobby-Eberly Telescope (HET). During this period the
  HET was used for science approximately two weeks per month centered
  on new moon. We discuss the types of science program that are bets
  suited to the unique nature of the HET and give examples of survey and
  synoptic observations that are on-going. The Marcario Low Resolution
  Spectrograph is the only facility instrument currently in service,
  so the science result from this instrument are emphasized. Future
  facility instruments are briefly discussed, along with a description
  of current HET performance.

Title: VizieR Online Data Catalog: Library of FOE spectra of late-type
    stars (Montes, 1999)
Authors: Montes, D.; Ramsey, L. W.; Welty, A. D.
Bibcode: 2000yCat..21230283M
Altcode:
  We present a library of Penn State Fiber Optic Echelle (FOE)
  observations of a sample of field stars with spectral types F to M and
  luminosity classes V to I. The spectral coverage is from 3800 to 10000Å
  with a nominal resolving power of 12,000. These spectra include many
  of the spectral lines most widely used as optical and near-infrared
  indicators of chromospheric activity such as the Balmer lines (Hα
  to Hδ), Ca II H &amp; K, the Mg I b triplet, Na I D<SUB>1</SUB>,
  D<SUB>2</SUB>, He I D<SUB>3</SUB>, and Ca II IRT lines. There are also
  a large number of photospheric lines, which can also be affected by
  chromospheric activity, and temperature-sensitive photospheric features
  such as TiO bands. The spectra have been compiled with the goal of
  providing a set of standards observed at medium resolution. We have
  extensively used such data for the study of active chromosphere stars
  by applying a spectral subtraction technique. However, the data set
  presented here can also be utilized in a wide variety of ways ranging
  from radial velocity templates to study of variable stars and stellar
  population synthesis. This library can also be used for spectral
  classification purposes and determination of atmospheric parameters
  (T<SUB>eff</SUB>, logg, [Fe/H]). A digital version of all the fully
  reduced spectra is available via ftp and the World Wide Web (WWW)
  in FITS format. (1 data file).

Title: Aplanatic Corrector Designs for the Extremely Large Telescope
Authors: Moretto, Gil; Sebring, Thomas A.; Ray, Frank B.; Ramsey,
   Lawrence W.
Bibcode: 2000ApOpt..39.2805M
Altcode:
  The next century is knocking on our door, bringing with it the
  possibility of telescopes even bigger than the 8-10-m-class instruments
  that have proliferated over the past decade. The fixed spherical
  reflector is the most economical and pragmatic way to construct an
  extremely large primary mirror (30-50 m in diameter). Although spherical
  mirrors have virtues such as manufacturability and identically figured
  segments, they also create great amounts of spherical aberration and
  coma. Here we show that there are several catoptric (all-reflecting)
  corrector designs that enable a fast telescope based on a spherical
  primary mirror.

Title: Spectra of Early and Late(r) Methane Dwarfs in the SDSS
    and 2MASS
Authors: Geballe, T. R.; Leggett, S. K.; Fan, X.; Schneider, D. P.;
   Knapp, G. K.; McDaniel, A.; Gunn, J. E.; Lupton, R. H.; Strauss,
   M. A.; Golimowski, D. A.; Henry, T.; Peng, E.; Tsvetanov, Z. I.;
   Uomoto, A.; Zheng, W.; Hill, G. J.; Ramsey, L. W.
Bibcode: 2000AAS...196.0306G
Altcode: 2000BAAS...32..678G
  We have obtained high quality 1-2.5 microns spectra of three cool brown
  dwarfs, recently identified in the Sloan Digital Sky Survey and one cool
  brown dwarf from the Two Micron All Sky Survey. JHK photometry of the
  three SDSS objects, which had been photometrically selected from their
  i'-z' colors as likely methane dwarfs, suggested that they could be
  "transition objects" between the L and T classes of brown dwarfs. Their
  spectra, obtained by CGS4 on UKIRT, contain both CO and CH<SUB>4</SUB>
  features, as well as H<SUB>2</SUB>O bands. The CH<SUB>4</SUB> bands
  are weaker than those in all other methane dwarfs reported to date. The
  strengths of the bands of these three molecules are different in each
  object, and together the spectra form a sequence linking the late L-type
  dwarfs and previously observed T dwarfs. We propose that these SDSS
  objects represent the early subclasses of the T classification. In the
  2MASS object, Gl 570D, identified by Burgasser et al. (astro-ph/0001194)
  as being significantly cooler than other methane dwarfs, the bands of
  CH<SUB>4</SUB> and H<SUB>2</SUB>O are deeper and in some cases broader
  than in any other known T dwarf, further narrowing the windows short
  of 3 microns where radiation can easily escape.

Title: Observations of Faint, Hard-Band X-Ray Sources in the Field
    of CRSS J0030.5+2618 with the Chandra X-Ray Observatory and the
    Hobby-Eberly Telescope
Authors: Brandt, W. N.; Hornschemeier, A. E.; Schneider, D. P.;
   Garmire, G. P.; Chartas, G.; Hill, Gary J.; MacQueen, P. J.; Townsley,
   L. K.; Burrows, D. N.; Koch, T. S.; Nousek, J. A.; Ramsey, L. W.
Bibcode: 2000AJ....119.2349B
Altcode: 2000astro.ph..2121B
  We present results from a study of 2-8 keV X-ray sources detected by
  the Advanced CCD Imaging Spectrometer on the Chandra X-Ray Observatory
  in the field of the z=0.516 cluster CRSS J0030.5+2618. In our 63.5
  arcmin<SUP>2</SUP> search area, we detect 10 sources with 2-8 keV
  fluxes down to ~4×10<SUP>-15</SUP> ergs cm<SUP>-2</SUP> s<SUP>-1</SUP>
  our lowest flux sources are ~10 times fainter than those previously
  available for study in this band. Our derived source density is about
  an order of magnitude larger than previous source counts above 2
  keV, although this density may be enhanced somewhat because of the
  presence of the cluster. We detail our methods for source detection
  and characterization, and we show that the resulting source list
  and parameters are robust. We have used the Marcario Low-Resolution
  Spectrograph on the Hobby-Eberly Telescope to obtain optical spectra
  for several of our sources; by combining these spectra with archival
  data, we find that the sources appear to be active galaxies, often
  with narrow permitted lines, red optical continua, or hard X-ray
  spectra. Four of the X-ray sources are undetected to R=21.7; if they
  reside in L<SUP>*</SUP> galaxies they must have z&gt;0.55-0.75 and
  hard X-ray luminosities of L<SUB>2-8</SUB>&gt;~4×10<SUP>42</SUP>
  ergs s<SUP>-1</SUP>. We detect all but one of our 2-8 keV sources
  in the 0.2-2 keV band as well. This result extends to significantly
  lower fluxes the constraints on any large, completely new population
  of X-ray sources that appears above 2-3 keV. Based on observations
  obtained with the Hobby-Eberly Telescope, which is a joint project
  of the University of Texas at Austin, Pennsylvania State University,
  Stanford University, Ludwig-Maximillians-Universität München, and
  Georg-August-Universität Göttingen.

Title: The Extremely Large Telescope (ELT), a scientific opportunity;
    an engineering certainty
Authors: Sebring, T. A.; Moretto, G.; Bash, F. N.; Ray, F. B.; Ramsey,
   L. W.
Bibcode: 2000ESOC...57...53S
Altcode: 2000elt..conf...53S
  No abstract at ADS

Title: Pennsylvania State University, Astronomy and Astrophysics,
    University Park, Pennsylvania 16802-6305. Report for the period 1
    Sep 1998 - 31 Aug 1999.
Authors: Sambruna, R.; Ramsey, L.
Bibcode: 2000BAAS...32..418S
Altcode:
  No abstract at ADS

Title: The Low-Resolution Spectrograph of the Hobby-Eberly
    Telescope. II. Observations of Quasar Candidates from the Sloan
    Digital Sky Survey
Authors: Schneider, D. P.; Hill, Gary J.; Fan, X.; Ramsey, L. W.;
   MacQueen, P. J.; Weedman, D. W.; Booth, J. A.; Eracleous, M.; Gunn,
   J. E.; Lupton, R. H.; Adams, M. T.; Bastian, S.; Bender, R.; Berman,
   E.; Brinkmann, J.; Csabai, I.; Federwitz, G.; Gurbani, V.; Hennessy,
   G. S.; Hill, G. M.; Hindsley, R. B.; Ivezić, Z.; Knapp, G. R.; Lamb,
   D. Q.; Lindenmeyer, C.; Mantsch, P.; Nance, C.; Nash, T.; Pier, J. R.;
   Rechenmacher, R.; Rhoads, B.; Rivetta, C. H.; Robinson, E. L.; Roman,
   B.; Sergey, G.; Shetrone, M.; Stoughton, C.; Strauss, M. A.; Szokoly,
   G. P.; Tucker, D. L.; Wesley, G.; Willick, J.; Worthington, P.; York,
   D. G.
Bibcode: 2000PASP..112....6S
Altcode: 1999astro.ph.10306S
  This paper describes spectra of quasar candidates acquired during
  the commissioning phase of the Low-Resolution Spectrograph of the
  Hobby-Eberly Telescope. The objects were identified as possible quasars
  from multicolor image data from the Sloan Digital Sky Survey. The 10
  sources had typical r' magnitudes of 19-20, except for one extremely red
  object with r<SUP>'</SUP>~23. The data, obtained with exposure times
  between 10 and 25 minutes, reveal that the spectra of four candidates
  are essentially featureless and are not quasars, five are quasars
  with redshifts between 2.92 and 4.15 (including one broad absorption
  line quasar), and the red source is a very late M star or early L
  dwarf. Based on observations obtained with the Sloan Digital Sky Survey,
  which is owned and operated by the Astrophysical Research Consortium.

Title: Library of Medium-Resolution Fiber Optic Echelle Spectra of F,
    G, K, and M Field Dwarfs to Giant Stars
Authors: Montes, David; Ramsey, Lawrence W.; Welty, Alan D.
Bibcode: 1999ApJS..123..283M
Altcode: 1999astro.ph..1411M
  We present a library of Penn State Fiber Optic Echelle (FOE)
  observations of a sample of field stars with spectral types F to M and
  luminosity classes V to I. The spectral coverage is from 3800 to 10000
  Å with a nominal resolving power of 12,000. These spectra include many
  of the spectral lines most widely used as optical and near-infrared
  indicators of chromospheric activity such as the Balmer lines (Hα
  to Hɛ), Ca II H &amp; K, the Mg I b triplet, Na I D<SUB>1</SUB>,
  D<SUB>2</SUB>, He I D<SUB>3</SUB>, and Ca II IRT lines. There are also
  a large number of photospheric lines, which can also be affected by
  chromospheric activity, and temperature-sensitive photospheric features
  such as TiO bands. The spectra have been compiled with the goal of
  providing a set of standards observed at medium resolution. We have
  extensively used such data for the study of active chromosphere stars
  by applying a spectral subtraction technique. However, the data set
  presented here can also be utilized in a wide variety of ways ranging
  from radial velocity templates to study of variable stars and stellar
  population synthesis. This library can also be used for spectral
  classification purposes and determination of atmospheric parameters
  (T<SUB>eff</SUB>, logg, [Fe/H]). A digital version of all the fully
  reduced spectra is available via ftp and the World Wide Web (WWW)
  in FITS format.

Title: Supernova 1999bv in MCG +10-25-14
Authors: Hill, G. J.; Bergmann, M. P.; Howell, D. A.; Wheeler, J. C.;
   MacQueen, P. J.; Booth, J. A.; Adams, M. T.; Eracleus, M.; Tejada, C.;
   Cobos, F.; Garfias, F.; Cuervo, J.; Nicklas, H.; Mitsch, W.; Wesley,
   G. W.; Odoms, P. S.; Barczac, G.; Ramsey, L. W.; Barnes, T. G., III;
   Roman, B.; Nance, C.; Worthington, T.
Bibcode: 1999IAUC.7186....2H
Altcode: 1999IAUC.7186R...1H; 1999IAUC.7186B...1H
  G. J. Hill, McDonald Observatory, University of Texas, reports on behalf
  of the Hobby-Eberly Telescope (HET) Low Resolution Spectrograph (LRS)
  commissioning team (which also includes M. P. Bergmann, D. A. Howell,
  J. C. Wheeler, P. J. MacQueen, J. A. Booth, M. T. Adams, M. Eracleus,
  C. Tejada, F. Cobos, F. Garfias, J. Cuervo, H. Nicklas, W. Mitsch,
  G. W. Wesley, P. S. Odoms, G. Barczac, L. W. Ramsey, T. G. Barnes
  III, B. Roman, C. Nance, G. Hill, T. Worthington): "A low-resolution
  spectrogram (range 400- 1000 nm) of SN 1999bv was obtained on Apr. 21.37
  UT with the Marcario LRS, during first light commissioning of the
  instrument. The broad emission features seen by Jha et al. (IAUC 7150)
  at 667, 600, 475, and 402 nm are confirmed, and we note that the broad
  emission (FWHM 10 000 km/s) at 667 nm is consistent with slightly
  blueshifted H-alpha emission in the rest frame of the supernova. Such
  emission was also seen in SN 1993J, and is suspected to be an indication
  of transition, or hybrid type-II/type-Ib/c events, sometimes referred
  to as type IIb."

Title: Chromospheric Activity of ROSAT-discovered Weak-line T
    Tauri Stars
Authors: Montes, D.; Ramsey, L. W.
Bibcode: 1999ASPC..158..302M
Altcode: 1999ssa..conf..302M; 1998astro.ph..9117M
  We have started a high resolution optical observation program dedicated
  to the study of chromospheric activity in weak-lined T Tauri stars
  (WTTS) recently discovered by the ROSAT All-Sky Survey (RASS). It is
  our purpose to quantify the phenomenology of the chromospheric activity
  of each star determining stellar surface fluxes in the more important
  chromospheric activity indicators (Ca II H &amp; K, H_beta, H_alpha,
  Ca II IRT) as well as obtain the Li I abundance, a better determination
  of the stellar parameters, spectral type, and possible binarity. A
  large number of WTTS have been discovered by the RASS in and around
  differen star formation clouds.Whether these stars are really WTTS,
  or post-TTS, or even young main sequence stars is a matter of ongoing
  debate. However, we have centered our study only on objects for which
  very recent studies, of Li I abundance (greater than Pleiads of the same
  spectral type) or radio properties, clearly confirmed their pre-main
  sequence (PMS) nature. In this contribution we present preliminary
  results of our January 1998 high resolution echelle spectroscopic
  observations at the 2.1m telescope of the McDonald Observatory. We
  have analysed, using the spectral subtraction technique, the H_alpha
  and Ca II IRT lines of six WTTS (RXJ0312.8-0414NW, SE; RXJ0333.1+1036;
  RXJ0348.5+0832; RXJ0512.0+1020; RXJ0444.9+2717) located in and around
  the Taurus-Auriga molecular clouds. A broad and variable double-picked
  H_alpha emission is observed in RXJ0444.9+2717. Emission above the
  continuum in H_alpha and Ca II IRT lines is detected in RXJ0333.1+1036
  and a filling-in of these lines is present in the rest of the stars. Our
  spectral type and Li I EW deterninations confirm the PMS nature of
  these objects.

Title: A Long-Duration Flare on the X-ray/EUV Selected,
    Chromospherically Active Binary 2RE J0743+224
Authors: Montes, D.; Ramsey, L. W.
Bibcode: 1999ASPC..158..226M
Altcode: 1999ssa..conf..226M; 1998astro.ph..9118M
  2RE J0743+224 (BD +23 1799) is a chromospherically active star selected
  by X-rays and EUV emission detected in the Einstein Slew Survey
  and ROSAT Wide Field Camera (WFC) all sky survey, and classified
  as single-lined spectroscopic binary by (Jeffries et al. 1995). We
  present here high resolution echelle spectroscopic observations of
  this binary, obtained during a 10 night run 12-21 January 1998 using
  the 2.1m telescope at McDonald Observatory. These observations reveal
  it is a double-lined spectroscopic binary. A dramatic increase in
  the chromospheric emissions (H_alpha and Ca II IRT lines) is detected
  during the observations. Several arguments favor the interpretation of
  this behavior as an unusual long-duration flare. First the temporal
  evolution of the event is similar to the observed in other solar and
  stellar flares, with an initial impulsive phase characterized by a
  strong increase in the chromospheric lines (the H_alpha EW change in a
  factor of 5 in only one day) and thereafter, the line emission decreased
  gradually over several days. Second, a broad component in the H_alpha
  line profile is observed just at the beginning of the event. Third,
  the detection of the He I D_{3} in emission and a filled-in He I 6678
  A. We detect a Li I 6708 A line enhancement which is clearly related
  with the temporal evolution of the flare. The maximum Li I enhancement
  occurs just after the maximum chromospheric emission observed in the
  flare. We suggest that this Li I is produced by spallation reactions in
  the flare. This is the first time that such Li I enhancement associate
  with a stellar flare is reported, and probably the long-duration of
  this flare is a key factor for this detection.

Title: The Hobby*Eberly Telescope, a Tool for Spectroscopic
    Astrophysics Introduction
Authors: Ramsey, L. W.
Bibcode: 1998AAS...193.2601R
Altcode: 1998BAAS...30Q1285R
  The Hobby*Eberly telescope (HET), which is currently in commissioning,
  is a special purpose telescope that represents a unique approach to
  ground based visible and near infrared astronomy. The US community
  will have several weeks per year of queue scheduled nights on the HET
  via National Science Foundation support of instrumentation. The focus
  of this session is how the Hobby*Eberly telescope is being deployed
  to meet the science goals of the partners and the US community at
  large. Invited talks will emphasize the scientific promise, as well
  as the instrumental and particular scheduling capabilities of the
  HET. Poster papers will detail the instrumental capabilities as well
  as how one can prepare to best utilize the HET.

Title: Visible and Near-IR Astrophysics at Medium Resolution with
    the Hobby-Eberly Telescope
Authors: Ciardullo, R.; Ramsey, L. W.
Bibcode: 1998AAS...193.2604C
Altcode: 1998BAAS...30.1285C
  The Medium Resolution Spectrograph (MRS) is a versatile, fiber-fed,
  dual beam echelle spectrograph for optical and near-IR observations with
  the Hobby-Eberly Telescope. Its high efficiency, excellent velocity
  stability, broad wavelength coverage, wide range of resolving power
  (3500 &lt; R &lt; 20,000), and many observing modes (including synthetic
  long-slit, multi-object, and integral field) make the instrument
  ideal for a wide range of scientific investigations. We review some of
  the major programs the MRS will undertake during its first few years
  of service, paying particular attention to those projects that will
  exercise the unique capabilities of the instrument and the telescope.

Title: Li I enhancement during a long-duration stellar flare
Authors: Montes, David; Ramsey, Lawrence W.
Bibcode: 1998A&A...340L...5M
Altcode: 1998astro.ph.10232M
  We report the possible detection of a Li I λ6708 Angstroms line
  enhancement during an unusual long-duration optical flare in the
  recently discovered, X-ray/EUV selected, chromospherically active
  binary 2RE J0743+224. The Li I equivalent width (EW) variations follow
  the temporal evolution of the flare and large changes are observed in
  the intensity of the line. The maximum Li I enhancement (40% in EW)
  occurs just after the maximum chromospheric emission observed in the
  flare. A significant increase of the (6) Li/(7) Li isotopic ratio is
  also detected. No significant simultaneous variations are detected
  in other photospheric lines. Neither line blends nor starspots seem
  to be the primary cause of the observed Li I line variation. From all
  this we suggest that this Li I enhancement is produced by spallation
  reactions during the flare.

Title: Hobby-Eberly Telescope: current status
Authors: Barnes, T. G.; Ramsey, L. W.
Bibcode: 1998AAS...193.2602B
Altcode: 1998BAAS...30Q1285B
  The Hobby-Eberly telescope (HET) is well into its second year of
  commissioning and rapid progress is being made on all HET systems. We
  report on the current pointing, tracking and image quality performance
  of the HET. We also outline plans for further improvement and estimate
  the performance we expect at the commencement of early operations
  sometime in the first half of 1999. Finally we will lay out expected
  science availability of HET facility instrumentation.

Title: Spider: The Formated Field Unit for the Hobby Eberly Telescope
Authors: Andersen, D. R.; Bershady, M. A.; Ramsey, L. W.
Bibcode: 1998AAS...193.1005A
Altcode: 1998BAAS...30.1263A
  We describe the Formated Field Unit (FFU) under construction at Penn
  State University for the 9m Hobby-Eberly Telescope's (HET) Medium
  Resolution Spectrograph (MRS): Spider. This FFU is an array of fiber
  optic cables formatted optimally to spectrally image single, extended,
  axi-symmetric sources, such as galaxies and planetary nebulae. The
  FFU consists of four, 15 arcsecond long slits with a common center
  but at four position angles (like an aserisk, or spider). Each slit
  is sampled by 1 arcsec diameter fibers (200 mu m), spaced 1.3 arcsec
  apart. Spider will be installed during the commissioning phase of the
  MRS (mid 1999). This fiber-fed echelle spectrograph has a resolution
  of 10,900 for a 1 arcsec aperture, and initial spectral coverage from
  0.5-0.95 mu m in a red beam. The large telescope aperture and fiber
  size of Spider yields large etendue (50 m(2) arcsec(2) ). There are
  currently no fiber arrays either planned or in existence which are
  comparable. Hence this FFU fills a niche for moderate resolution
  spectroscopy at low surface-brightness. The FFU is expected to reach
  a limiting surface-brightness in V of 22 at S/N = 10 per spectral
  resolution element per fiber at R = 10,900 in one hour; this assumes a
  peak throughput of 15% for the HET plus MRS system. In this presentation
  we outline the expected performance, design and construction progress
  to date, and our characterization of fiber packing quality and focal
  ratio degradation from test arrays. We also demonstrate how the Spider
  FFU can be used for kinematic studies nearby and moderately distant
  galaxies. The fiber array will be capable of delivering simultaneous
  rotation curves and disk velocity dispersions over a range of look-back
  times. This research is supported by NSF/AST 96-18849.

Title: Optical Fiber Evaluation for the Hobby-Eberly Telescope
Authors: McGouldrick, K.; Maywalt, J.; Engel, L.; Rhoads, B.; Andersen,
   D. R.; Ramsey, L. W.
Bibcode: 1998AAS...193.1006M
Altcode: 1998BAAS...30.1263M
  Two major facility instruments on the Hobby-Eberly telescope
  (HET) are fiber coupled: the high and medium resolution
  spectrographs. Understanding the behavior of the fibers with the HET is
  central to understanding the performance of the telescope/spectrograph
  system. We will describe the Penn State fiber evaluation facility
  which enables us to measure focal ratio degradation (FRD) and total
  throughput. We will present some typical data obtained using the HET
  focal ratio at the fiber input. The HET design has a roving pupil that
  changes the illumination pattern somewhat during the typical 1 hour
  tracking time on a target. We will describe our plans to simulate the
  HET input test the degree to which the varying pupil is scrambled by
  the fiber.

Title: The Hobby-Eberly Telescope Commissioning Status
Authors: Adams, M. T.; Barnes, T. G.; Booth, J. A.; Ramsey, L. W.
Bibcode: 1998AAS...193.1001A
Altcode: 1998BAAS...30Q1262A
  The Hobby-Eberly Telescope (HET) is unique among the new generation of
  8 meter class telescopes in that it establishes a new cost paradigm
  for large aperture science by making considered trades between cost
  and performance. We briefly review the HET optical design and the
  as-built facility. We discuss the status and performance of the major
  HET systems. We describe the intense commissioning period that has
  been underway since September 1997 and outline plans to ramp HET into
  science operations this coming year.

Title: The J-band camera system for the Hobby-Eberly telescope
Authors: Beatty, J. J.; Charlton, J. C.; Churchill, C. W.; Ramsey,
   L. W.
Bibcode: 1998AAS...193.1002B
Altcode: 1998BAAS...30.1262B
  The J-band camera system, or JCAM, is an simple extension to the current
  HET commissioning spectrograph to allow moderate resolving power (7,000
  &lt; R &lt; 13,000) spectroscopy in the near-infrared. The JCAM system
  will replace the current echelle grating, cross disperser, camera,
  and detector in the Upgraded Fiber Optic Echelle (UFOE) currently at
  the HET site. The camera has a five element all-refracting design. The
  detector system is a 1024x1024 Hawaii array housed in an IR Labs
  dewar and provides full coverage from 0.98 - 1.34 microns in a single
  exposure. The detector electronics utilizes a VME-based PC driving
  custom control and signal processing electronics. At the resolution of
  JCAM only ~ 10% of the spectrum is contaminated by night sky lines. It
  will be possible to obtain S/N ~ 30 per resolution element in one hour
  on a J=18 object.

Title: The Medium Resolution Spectrograph for the Hobby Eberly
telescope: Capability and Performance Goals
Authors: Ramsey, L. W.; Engel, L.; Rhoads, B.; Maywalt, J.;
   McGouldrick, K.; Andersen, D. R.
Bibcode: 1998AAS...193.1007R
Altcode: 1998BAAS...30.1263R
  The Medium Resolution Spectrograph (MRS) is a versatile, fiber-fed dual
  beam echelle spectrograph for the Hobby-Eberly Telescope (HET). This
  instrument is designed for a wide range of scientific investigations;
  it includes single-fiber inputs for the study of point-like sources,
  synthetic slits of fibers for long slit spectroscopy, multi-fiber
  inputs for multi-object spectroscopy, and an optical fiber integral
  field unit. The MRS will have resolving power ranging from 3500 to
  20,000 depending on the fiber/slit combination selected. The initial,
  visible wavelength beam will have wavelength coverage from 450 -
  900 nm in a single exposure. Later, a second beam operating in the
  near-infrared will be added which will have coverage of 950-1300 nm in
  a single exposure and capability out to 1800 nm. We detail the fiber
  input and spectral coverage options on the HET as well as present
  performance goals.

Title: Detection of Li i enhancement during a long-duration flare
    in the recenltly discovered X-ray selected, chromospherically active
    binary 2RE J0743+2 24
Authors: Montes, David; Ramsey, Lawrence W.
Bibcode: 1998AAS...192.8203M
Altcode: 1998BAAS...30Q1155M; 1998astro.ph..6227M
  We report the detection of a long-duration optical flare in the
  recenltly discovered, X-ray selected, chromospherically binary 2RE
  J0743+224. The high resolution echelle spectroscopic observations taken
  in 12-21th January 1998 exhibit a dramatic increase in the chromospheric
  emissions (Hα and Ca ii IRT lines) that we interpret as a flare based
  on: the temporal evolution of the event, the broad component observed
  in the Hα line profile, the detection of the He i D<SUB>3</SUB> in
  emission and a filled-in He i 6678 Angstroms. During these obsevations
  we detect a Li i 6708 Angstroms line enhancement which is clearly
  related with the temporal evolution of the flare. The maximum Li i
  enhancement (20% in EW) occurs just after the maximum chromospheric
  emission observed in the flare. A significant increase of the (6) Li/(7)
  Li isotopic ratio is also detected. For all this we suggest that this Li
  i enhancement is produced by spallation reactions during the flare. This
  is the first time that such Li i enhancement associate with a stellar
  flare is reported, and probably the long-duration of this flare is a
  key factor for this detection. A large fraction of the stellar surface
  seem to be covered by starspots during the event, as we deduce for
  the analysis of the TiO 7055 Angstroms band, thus taken into account
  the Li i is very temperature sensitive, we can not discard that this
  Li i variations was related the presence of starspots. However, the
  correlation with the temporal evolution of the flare, the no detection
  of changes in the other photospheric absorption lines, and the large
  changes observed in the core of the Li i, as predict the models, argue
  in favour of the hipothesis that the Li i is produced during the flare.

Title: Early performance and present status of the Hobby-Eberly
    Telescope
Authors: Ramsey, Lawrence W.; Adams, M. T.; Barnes, Thomas G.; Booth,
   John A.; Cornell, Mark E.; Fowler, James R.; Gaffney, Niall I.;
   Glaspey, John W.; Good, John M.; Hill, Gary J.; Kelton, Philip W.;
   Krabbendam, Victor L.; Long, L.; MacQueen, Phillip J.; Ray, Frank B.;
   Ricklefs, Randall L.; Sage, J.; Sebring, Thomas A.; Spiesman, W. J.;
   Steiner, M.
Bibcode: 1998SPIE.3352...34R
Altcode:
  The Hobby-Eberly telescope (HET) is a recently completed 9- meter
  telescope designed to specialize in spectroscopy. It saw first light in
  December 1996 and during July 1997, it underwent its first end-to-end
  testing acquiring its first spectra of target objects. We review the
  basic design of the HET. In addition we summarize the performance of
  the telescope used with a commissioning spherical aberration correlator
  and spectrograph, the status of science operations and plans for the
  implementation of the final spherical aberration corrector and facility
  class instruments.

Title: Extremely large telescope: further adventures in feasibility
Authors: Sebring, Thomas A.; Bash, Frank N.; Ray, Frank B.; Ramsey,
   Lawrence W.
Bibcode: 1998SPIE.3352..792S
Altcode:
  Should the astronomical community pursue development of telescopes
  10 times larger than the 8 and 10 meter individual and arrayed
  telescopes currently under development or recently commissioned? The
  question devolves into two parts: Is construction of such a telescope
  feasible from an engineering and cost standpoint? Does the scientific
  benefit justify the probable cost of such development? An Extremely
  Large Telescope (ELT) has previously been proposed based on the
  Arecibo type design employed in the recently completed Hobby Eberly
  Telescope. Analysis of the performance and scientific viability
  of the ELT shows that it can have an important role in near and IR
  spectroscopy for cosmology providing that stringent image and background
  performance requirements are met. Further development of engineering
  design and interaction with the manufacturing community conclusively
  shows that not only is such a telescope feasible, but that the entire
  observatory can be constructed for of order $DLR250 million at a site
  likely to provide optimal optical seeing. It remains an issue for the
  scientific community to judge whether such capability provides benefits
  commensurate with the costs.

Title: Hobby-Eberly Telescope: commissioning experience and observing
    plans
Authors: Glaspey, John W.; Adams, M. T.; Booth, John A.; Cornell,
   Mark E.; Fowler, James R.; Krabbendam, Victor L.; Ramsey, Lawrence W.;
   Ray, Frank B.; Ricklefs, Randall L.; Spiesman, W. J.
Bibcode: 1998SPIE.3349...50G
Altcode:
  Experience in bringing into operation the 91-segment primary mirror
  alignment and control system, the focal plane tracker system, and
  other critical subsystems of the HET will be described. Particular
  attention is given to the tracker, which utilizes three linear and
  three rotational degrees of freedom to follow sidereal targets. Coarse
  time-dependent functions for each axis are downloaded to autonomous
  PMAC controllers that provide the precise motion drives to the two
  linear stages and the hexapod system. Experience gained in aligning
  the sperate mirrors and then maintaining image quality in a variable
  thermal environments will also be described. Because of the fixed
  elevation of the primary optical axis, only a limited amount of time
  is available for observing objects in the 12 degrees wide observing
  band. With a small core HET team working with McDonald Observatory
  staff, efficient, reliable, uncomplicated methodologies are required
  in all aspects of the observing operations.

Title: Hobby-Eberly Telescope medium-resolution spectrograph and
    fiber instrument feed
Authors: Horner, Scott D.; Engel, Leland G.; Ramsey, Lawrence W.
Bibcode: 1998SPIE.3355..399H
Altcode:
  The Medium Resolution Spectrograph (MRS) is a high throughput,
  versatile, fiber-fed echelle spectrograph for the Hobby-Eberly
  Telescope (HET). This instrument is designed for a wide range of
  scientific investigations; it includes single-fiber inputs for the
  study of point-like sources, synthetic slits of fibers for long slit
  spectroscopy, multi-fiber inputs for multi- object spectroscopy, and an
  optical fiber integral field unit. The MRS will have resolution settings
  between 3500 less than (lambda) /(Delta) (lambda) less than 21000 and
  will consist of two beams. The initial, visible wavelength beam will
  have wavelength coverage from 450 - 900 nm in a single exposure. This
  beam will also have capability in the ranges 390 - 450 and 900 -
  950 nm by altering the angles of the echelle and/or cross-disperser
  gratings. Later, a second beam operating in the near-infrared will be
  added which will have coverage of 950 - 1300 nm in a single exposure
  and capability out to 1800 nm. The HET Fiber Instrument Feed (FIF) is
  mounted at the focal plane of the telescope and positions the fibers
  feeding the MRS and the High Resolution Spectrograph (HRS). The unique
  and economical design of the FIF enables the HET's versatility in
  performing a wide range of scientific investigations with the telescope
  operating in a queue-scheduled mode.

Title: Multiwavelength Optical Observations of Chromospherically
    Active Binary Systems
Authors: Montes, D.; Sanz-Forcada, J.; Fernández-Figueroa, M. J.;
   de Castro, E.; Cornide, M.; Ramsey, L. W.
Bibcode: 1998Ap&SS.263..279M
Altcode: 1999Ap&SS.263..279M
  We summarize here our ongoing project of multiwavelength optical
  observations aimed at studying the chromosphere of active binary
  systems, using the information provided for several optical
  spectroscopic features, that are formed at different heights in the
  chromosphere.

Title: Galaxy Kinematics with Integral-Field Spectroscopy and the
    Hobby-Eberly Telescope
Authors: Bershady, M. A.; Andersen, D.; Ramsey, L.; Horner, S.
Bibcode: 1998ASPC..152..253B
Altcode: 1998fopa.proc..253B
  No abstract at ADS

Title: Fiber-Optic Instrumentation and the Hobby-Eberly Telescope
Authors: Ramsey, L. W.
Bibcode: 1998ASPC..152..235R
Altcode: 1998fopa.proc..235R
  No abstract at ADS

Title: The Hobby-Eberly telescope and facility instrumentation:
    a model facility for the Southern African large telescope.
Authors: Ramsey, L. W.
Bibcode: 1998salt.conf...19R
Altcode:
  The Hobby-Eberly telescope (HET) is a fundamentally different approach
  to building large telescopes. It provides an extremely economical
  path to large aperture and thus provides opportunity to scientists in
  countries with limited resources. As such it provides an excellent model
  for the Southern African Large Telescope (SALT) project. Central to the
  HET approach is specialization: the HET is tailored for spectroscopy,
  and in particular, fibre-coupled spectroscopy. By limiting observational
  flexibility, cost-effective technical approaches have made it possible
  for the HET to break traditional cost vs. aperture laws. I will outline
  the science missions and capabilities of the HET facility instruments
  currently under construction.

Title: The Hobby-Eberly Telescope Fiber-Instrument Feed
Authors: Horner, S. D.; Engel, L. G.; Ramsey, L. W.
Bibcode: 1998ASPC..152..247H
Altcode: 1998fopa.proc..247H
  No abstract at ADS

Title: Integral Field Spectroscopy with the Hobby-Eberly Telescope
Authors: Andersen, D. R.; Bershady, M. A.; Ramsey, L. W.; Horner, S. D.
Bibcode: 1997AAS...191.4105A
Altcode: 1997BAAS...29.1270A
  We describe two fiber-optical arrays (IFUs) under construction
  at Penn State University for the 9m Hobby-Eberly Telescope's
  (HET) Medium Resolution Spectrograph (MRS). These arrays optimize
  integral-field spectroscopy for kinematic studies of individual,
  nearby and moderately distant galaxies, but will have more general
  application to moderate spectral resolution studies of extended
  sources at low surface-brightness. Once in place, the fiber arrays
  will be capable of delivering simultaneous rotation curve and disk
  velocity dispersion measurements over a range of look-back times. These
  measurements can be used to separately estimate the disk mass and
  total mass of galaxies. Such surveys would have important implications
  for the nature of dark matter. One array spans over 30 arcsec using 2
  arcsec (400 mu m) fibers to densely sample slits at 4 position angles
  at resolution from 5500 to 11000. The second array spans 15 arcsec
  using 1 arcsec fibers to densely sample a core area of ~ 60 arcsec(2)
  at resolution of 11000 to 14500. In contrast, fiber arrays planned
  for other 10m-class telescopes generally are optimized for smaller
  areas and higher angular resolution, but are commensurately limited to
  higher surface-brightness at fixed spectral resolution. Our 400 micron
  array will be installed during the commissioning phase of the MRS when
  this fiber-fed echelle spectrograph will have a resolution of 10,900
  for a 1 arcsec slit and spectral coverage from 0.5-0.95 mu m in a red
  beam. In this presentation we outline the expected performance, design
  and construction progress to date, and our initial characterization
  of fiber packing quality and focal ratio degradation from test arrays
  already completed. This research is supported by NSF/AST 96-18849.

Title: Hobby-Eberly Telescope: a progress report
Authors: Sebring, Thomas A.; Ramsey, Lawrence W.
Bibcode: 1997SPIE.2871...32S
Altcode:
  The Hobby-Eberly Telescope, nearing completion at McDonald Observatory
  in west Texas is an optical Arecibo-type telescope utilizing an 11-meter
  primary mirror and a 9.2-meter effective aperture. Innovative approaches
  have been employed to provide this large modern telescope at a total
  cost of $13.5 million. A joint project of the University of Texas,
  The Pennsylvania State University, Stanford University, the University
  of Munich, and the University of Goettingen, the telescope will be
  completed in mid 1997. First light is expected in mid 1996.

Title: Extremely large telescope: a twenty-five meter aperture for
    the twenty-first century
Authors: Bash, Frank N.; Sebring, Thomas A.; Ray, Frank B.; Ramsey,
   Lawrence W.
Bibcode: 1997SPIE.2871..576B
Altcode:
  The 10-meter class Hobby-Eberly telescope (HET), now nearing completion,
  provides technology for optical Arecibo-type telescopes which can be
  extrapolated to even larger apertures. Utilizing a fixed elevation angle
  and a spherical segmented primary mirror provides cost effective and
  pragmatic solutions to mirror mounting and fabrication. Arecibo-type
  tracking implies a greatly reduced tracking mass and no change to the
  gravity vector for the primary mirror. Such a telescope can address
  70 percent of the available sky and exhibit optical quality easily
  sufficient for effective spectroscopy and photometry. The extremely
  large telescope takes advantage of several key engineering approaches
  demonstrated by the HET project to achieve a cost comparable to
  similarly-sized radio rather than optical telescopes. These engineering
  approaches include: bolted pre-manufactured primary mirror truss,
  factory manufactured geodesic enclosure dome, air bearing rotation
  of primary mirror, tracker, and dome systems directly on concrete
  piers, and tracking via a hexapod system. Current estimates put the
  cost of the ELT at $200 million for a 25-meter aperture utilizing a
  33-meter primary mirror array. Construction of the ELT would provide
  the astronomy community with an optical telescope nearly an order
  of magnitude larger than even the largest telescopes in operation or
  under construction today.

Title: The Upgraded Fiber Optic Echelle Spectrograph
Authors: Harlow, J. J. B.; Ramsey, L. W.; Andersen, D. R.; Fleig,
   J. D.; Rhoads, B. T.; Engel, L. G.
Bibcode: 1996AAS...189.4207H
Altcode: 1996BAAS...28R1324H
  The Upgraded Fiber Optic Echelle (UFOE) is a fiber-fed, white pupil
  echelle spectrograph to be implemented at the Hobby-Eberly Telescope
  (HET) in the spring of 1997. It will serve as the commissioning
  spectrograph until HET facility instruments come on line in early
  1998. This instrument is a quick, cost effective upgrade of the
  Fiber Optic Echelle, resident at KPNO for a decade. The UFOE will be
  capable of R = 13,900 (Nyquist limited 2 pixels/resel), with complete
  spectral coverage from 530 nm to 850 nm and about 90% coverage to 900
  nm with adequate order separation. It utilizes a 2.5 meter radius 400
  mm diameter spherical mirror to reimage an ``average'' pupil between
  the echelle and the cross-dispersing grating onto the entrance pupil
  of a 200 mm f/2 camera lens. Due to the reduction of vignetting made
  possible with the pupil mirror, it is estimated that the UFOE will
  have an efficiency of 13% on the sky when used on the HET, whereas
  the FOE had an efficiency of 8%. This efficiency, combined with the 9
  meter aperture of the HET, should allow a limiting magnitude of V =
  18.9 for a 3000 second exposure with S/N = 30 per 1/2 resel. This
  spectrograph has been designed and constructed at Penn State and we
  present results of characterization of image quality, vignetting,
  and focal plane characteristics.

Title: A Performance Model for the Hobby-Eberly Telescope
Authors: Ramsey, L.; Gressler, W.; Hill, G. J.; Sebring, T.
Bibcode: 1995AAS...187.7401R
Altcode: 1995BAAS...27.1389R
  The Hobby-Eberly telescope's (HET) unique optical design makes
  deliberate trades between science performance and cost. To optimize the
  use of the telescope we require reliable modeling of the performance
  in order to efficiently plan observations. We describe the HET optical
  system design and present a performance model that gives the photon
  flux in the HET focal plane for sample targets under different seeing
  conditions. In addition we utilize this model and similar models of
  a focal plane and fiber spectrograph to estimate the HET limiting
  magnitudes at anticipated instrument spectral resolutions.

Title: The Hobby-Eberly Telescope: A Progress Report
Authors: Sebring, T. A.; Adams, M. T.; Ramsey, L. W.
Bibcode: 1995AAS...18712103S
Altcode: 1995BAAS...27.1453S
  The Hobby-Eberly Telescope (HET) Project has made substantial progress
  in design and construction of an 11-meter primary, 9-meter pupil,
  optical Arecibo-type telescope. Construction of the facility will be
  complete by early 1996 and will be followed by systems integration
  leading to engineering first light in the third quarter of 1996. The
  telescope structure and primary mirror truss are already in place and
  the telescope azimuth rotation system has been tested. The first dozen
  of the 91 identical mirror segments are complete.

Title: Beyond 10 Meter Apertures: The Extremely Large Telescope
Authors: Bash, F. N.; Sebring, T. A.; Ray, F. B.; Ramsey, L. W.
Bibcode: 1995AAS...187.7201B
Altcode: 1995BAAS...27.1387B
  An overview of a design concept for a highly cost effective telescope
  is presented which features an order of magnitude increase in
  light gathering power relative to the 10-meter class telescopes
  recently completed or currently under construction. The telescope
  is an Arecibo-type employing a segmented primary mirror 35 meters
  in diameter with a 28-meter pupil. The primary mirror array and the
  tracker system are supported on separate structures which mount to a
  common foundation. Azimuth rotation is achieved utilizing air bearings
  between observations. The total estimated cost for this telescope
  is on the order of \$100 million, making it far less expensive than
  full-sky designs previously proposed. The ELT employs technology
  which has been successfully demonstrated in the construction of the
  Hobby-Eberly Telescope.

Title: The Activity of Weak-Lined T Tauri Stars. I. V410 Tauri
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1995AJ....110..336W
Altcode:
  From two intensive series of spectra we have studied the phenomenology
  of magnetic activity and its distribution on and around V410
  Tau. Large-amplitude, quasisinusoidal radial velocity variations at the
  stellar rotation period appear to be due to large-scale photospheric
  temperature inhomogeneity that has been present at least since 1988,
  and not to orbital motion. Other radial velocity variations imply
  more localized spot groups. The radial velocity variations highlight
  the point that radial velocity searches for brown dwarfs and planets
  orbiting cool stars must take stellar activity into account. The
  activity-related radial velocity variations seen in V410 Tau are
  thousands of times larger than expected radial velocity reflex
  motion of low-mass stars due to planets. Variations of absorption
  linewidths are consistent with surface temperature inhomogeneities
  implied by the radial velocity variations. The implied temperature
  distribution is in qualitative with Doppler images made from one
  of our series of spectra. We found that the cooler regions of the
  photosphere were associated with greater Balmer emission during the
  first observing run, but about 90° out of phase 13 months later. The
  level of Balmer emission increased from one season to the next,
  and flares were observed only during the later season, suggesting
  an activity cycle. The net Balmer emission apparently has two strong
  contributors: a global chromospheric component and a variable asymmetric
  "halo." Prominence-like structures appear not to be a large contributor
  to the nonphotospheric Balmer features. Transient absorption features
  probably are due to an infall of previously ejected material.

Title: Hobby-Eberly telescope medium-resolution spectrograph
Authors: Ramsey, Lawrence W.
Bibcode: 1995SPIE.2476...20R
Altcode:
  We present a concept design for a versatile, high throughput fiber
  couple spectrograph for the 9-meter Hobby-Eberly telescope. This
  instrument, designated the medium resolution spectrograph (MRS) will
  cover the visible spectrum from 350 nm to 1100 nm and have a resolution
  range 300 &lt; (lambda) /(Delta) (lambda) &lt; 20000. It will reside
  in an environmentally controlled spectrograph room. Operating modes of
  the spectrograph will include single object, synthetic long slit, and
  multiple object spectroscopy. The dual requirements of spectral coverage
  and high resolution mandate that the MRS be a dual beam instrument.

Title: The Hobby-Eberly Telescope; Status and Science Capability
Authors: Ramsey, Lawrence W.
Bibcode: 1995AAS...186.4401R
Altcode: 1995BAAS...27..874R
  The Hobby-Eberly Telescope (HET), currently under construction at
  McDonald Observatory, is a unique approach to large telescope system
  design. The HET, formerly called the Spectroscopic Survey Telescope
  before its groundbreaking in March 1994, has a number of unique
  features that allow it to meet its science mission with unusual cost
  effectiveness. This fixed altitude design has a spherical primary mirror
  consisting of 91 identical hexagonal segments made of low expansion
  glass with a total collecting area of 77.6 square meters. The pupil
  of the HET varies from a maximicrons diameter of 9 meters as an all
  reflecting spherical aberration corrector tracks the astronomical target
  on the spherical focal surface of the primary mirror. This tracking
  is accomplished with a multi-axis system that provides precision
  motions and minimal pupil obstruction. A final focal plane field of
  view of 4 arc minutes at f/4.7 will deliver seeing limited images at
  the McDonald site. A combination of a 35 degree tilt from zenith. The
  HET is well suited to spectroscopic follow-up of objects from wide
  field ground based and space based surveys. Instrumentation planned
  for the HET include a low resolution imaging spectrograph in the focal
  plane and fiber coupled medium and high resolution instruments. The
  fiber feeds allow rapid switching of instruments compatible with a
  queue scheduled observing mode. Anticipated performance of the HET
  with such instruments will be present along with the current status
  of the project. First light is expected in 1996.

Title: On the Role of Mass Transfer in X-Ray Emission of RS CVN
    Systems
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1995AJ....109.2187W
Altcode:
  We explore the possible role of mass transfer in generating x rays
  in RS CVn binary systems. We have used system properties from the
  published literature. We also present results of our ROSAT PSPC pointed
  observations of RT Lacertae and SS Boötis. We find the evidence
  that mass transfer is responsible for significant x-ray emission to
  be suggestive, but not conclusive. Fundamental stellar and orbital
  parameters and distances must be determined to good precision for more
  RS CVn systems before progress on this question can be made.

Title: The Activity of Weak-Lined T Tauri Stars
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1995AAS...186.0904W
Altcode: 1995BAAS...27..824W
  We have conducted intensive spectroscopic observing campaigns on
  several weak-lined and classical T Tauri stars (WTTS, CTTS). The data
  were obtained with the Penn State Fiber Optic Echelle spectrograph in
  three observing runs at the KPNO 2.1m telescope. We wish to understand
  the phenomenology of stellar and circumstellar activity of our targets,
  and to quantify the activity where possible. Here we present results
  for our WTTS targets, V410 Tau in particular. The first step in our
  analysis is to determine the spectral type of each target by fitting a
  grid of standard star spectra to the target star spectra. Byproducts of
  this process are values for radial and projected rotational velocities
  and veiling for each observation. We find no veiling (from Hβ to
  Hα ) in any of our targets. Results for V410 Tau are dramatic. The
  photospheric temperature distribution (recently Doppler imaged by
  Strassmeier, Welty, &amp; Rice 1994 and Hatzes 1995) causes line
  profile variations which cause apparent radial velocity changes. The
  amplitude of this variability is 500 times the Sun's orbital motion due
  to Jupiter. Although this is an extreme case, it serves to illustrate
  the point that radial velocity searches for low mass companions,
  especially planets, must take stellar activity into account. Three
  of our other WTTS targets show similar radial velocity variation. We
  also feature flare observations of V410 Tau. One event was observed
  rising and declining during one observing night. Its total duration was
  about 15 hours. It released ~ 10(35) erg in optical line emission. He
  D_3 radial velocities enable us to locate the flare with respect to
  features in the Doppler images. Our results suggest that V410 Tau has
  entered a state of relatively high activity after a decline indicated
  by various observations made during the 1980s. We will also be pleased
  to discuss results on our CTTS targets with interested parties.

Title: The Shape of FK Comae Berenices: Evidence for a Recently
    Coalesced Binary
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1994ApJ...435..848W
Altcode:
  To explain its great rotational speed, it has been argued that
  FK Comae Berenices is either a recently coalesced binary or has
  been spun up by angular momentum transfer via mass transfer from
  an unseen companion. Upper limits on radial velocity variation put
  severe constraints on any binary model. A series of 51 spectroscopic
  observations of FK Com during an eight night observing run in 1989
  revealed regular variation of projected rotational speed with rotational
  phase. These variations are suggestive of strong nonradial pulsations
  at about half the rotational period. We postulate that the pulsations
  were excited by a recent binary merger. Less extensive data obtained in
  1987 and 1992 show different patterns of line-width variation. Thus
  it appears that the pulsation spectrum is changing on timescales
  significantly less than two years.

Title: ROSAT Observations of FK Comae Berenices
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1994AJ....108..299W
Altcode:
  We obtained ROSAT PSPC observations of FK Com over a period of 24.4 h,
  or 0.42 rotation. During the observations the x-ray flux increased by
  a factor of at least 5 before declining toward its previous level. A
  single temperature Raymond-Smith model is adequate to model the low
  signal-to-noise ratio spectrum from each observation interval. Initially
  the spectrum was that of a 8.5 x 10<SUP>6</SUP> K plasma, with L9sub
  x)=0.66 x 10<SUP>31</SUP> erg s<SUP>-1</SUP>. When the x-ray flux was
  greatest, the model plasma temperature rose to 2.5 x 10<SUP>7</SUP>
  K, and L<SUB>x</SUB>=3.46 x 10<SUP>31</SUP> ergs<SUP>-1</SUP>. During
  the post-maximum decline in luminosity the plasma temperature was
  approximately 12 x 10<SUP>6</SUP> K. We conclude that the increase of
  x-ray flux recorded by ROSAT was due to an x-ray flare with a 1.5 h
  decline time scale.

Title: Spectroscopic survey telescope project
Authors: Ramsey, Lawrence W.; Sebring, Thomas A.; Sneden, Christopher
   A.
Bibcode: 1994SPIE.2199...31R
Altcode:
  We describe the concept, basic design and capability of an eight
  meter class telescope currently being constructed by a international
  consortium of universities led by The Pennsylvania State University
  and The University of Texas at Austin. This unique telescope concept
  represents a deliberate trade between the science mission and technical
  cost drives. The basic science driver for the Spectroscopic Survey
  Telescope has traditionally been the need to obtain a large number of
  spectroscopic exposures in a short time. An efficient design that meets
  this need is a tilted Arecibo type telescope with a large segmented
  primary mirror. The SST has a number of other unique features that
  allow it to meet its science mission with unusual cost effectiveness.

Title: Design and status of the Spectroscopic Survey Telescope
Authors: Sebring, Thomas A.; Booth, John A.; Good, John M.; Krabbendam,
   Victor L.; Ray, Frank B.; Ramsey, Lawrence W.
Bibcode: 1994SPIE.2199..565S
Altcode:
  The Spectroscopic Survey Telescope is being constructed by a consortium
  of universities at McDonald Observatory in the Davis Mountains of
  Texas. Principal partners are the University of Texas at Austin and
  the Pennsylvania State University. Also participating are Stanford
  University and the University of Munich and University of Gottingen in
  Germany. We describe the specific design attributes which enable the SST
  to be constructed for a fraction of the cost of astronomical telescopes
  of comparable size. Such unique features as identical spherical mirror
  segments, selective figuring for constant mirror mount deformation,
  air bearing azimuth rotation system, and pre-fabricated architectural
  type domes are employed. Emphasis is on simplification of design,
  reduction of part count and mass, and utilization of lessons learned
  from other recent large telescope projects.

Title: Eclipse Observations of RS CVN Binaries II. A Parametric
    Model of Extended Matter
Authors: Hall, Jeffrey C.; Ramsey, Lawrence W.
Bibcode: 1994AJ....107.1149H
Altcode:
  We have surveyed ten RS CVn binary systems and have detected large
  regions of extended, prominencelike material which we have shown to be
  a common feature in these systems. These extended regions are apparent
  as anomalous absorption features in the spectra when they obscure the
  disk of the eclipsed star and as weak emission features when they
  appear with no disk behind. We have constructed a first-generation
  model to verify the general prominencelike nature of the material and to
  estimate its extent and its most basic physical characteristics. In this
  paper we present our results of our modeling on four of the systems in
  our survey that showed clear signatures of extended material: AW Her,
  MM Her, SS Boo, and UV Psc. We find that these stellar prominencelike
  structures are very much larger than their solar counterparts, though
  their gross physical characteristics (i.e., their electron density
  and temperature and their general appearance as tenuous, vertically
  oriented, magnetically confined structures) are similar to those seen
  in solar prominences. These features appear to evolve fairly rapidly,
  since moderate- to high-velocity flows ranging from several tens of
  km/s to 170 km/s are apparent. However, in at least one case (SS Boo)
  they are recurrent over a time scale of at least a year. We conclude
  by discussing the implications of this work regarding the nature of
  close binary star active structures and their evolution.

Title: Sleuthing the Dynamo: HST/FOS Observations of UV Emissions
    of Solar-Type Stars in Young Clusters
Authors: Ayres, T.; Basri, G.; Simon, T.; Stauffer, J.; Stern, R.;
   Antiochos, S.; Bookbinder, J.; Brown, A.; Doschek, G.; Linsky, J.;
   Ramsey, L.; Walter, F.
Bibcode: 1994ASPC...64...53A
Altcode: 1994csss....8...53A
  No abstract at ADS

Title: A Far-Ultraviolet Flare on a Pleiades G Dwarf
Authors: Ayres, T. R.; Stauffer, J. R.; Simon, Theodore; Stern, R. A.;
   Antiochos, S. K.; Basri, G. S.; Bookbinder, J. A.; Brown, A.; Doschek,
   G. A.; Linsky, J. L.; Ramsey, L. W.; Walter, F. M.
Bibcode: 1994ApJ...420L..33A
Altcode:
  The Hubble Space Telescope/Faint Object Spectrograph (HST/FOS) recorded
  a remarkable transient brightening in the C IV lambda lambda 1548,50
  emissions of the rapidly rotating Pleiades G dwarf H II 314. On the one
  hand the 'flare' might be a rare event luckily observed; on the other
  hand it might be a bellwether of the coronal heating in very young
  solar-mass stars. If the latter, flaring provides a natural spin-down
  mechanism through associated sporadic magnetospheric mass loss.

Title: ROSAT Observations of FK Comae Berenices
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1994ASPC...64..146W
Altcode: 1994csss....8..146W
  No abstract at ADS

Title: Spectroscopic Monitoring of V410 Tauri
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1994ASPC...64..495W
Altcode: 1994csss....8..495W
  No abstract at ADS

Title: The Spectroscopic Survey Telescope: Concept and Performance
Authors: Ramsey, Lawrence W.
Bibcode: 1994ASPC...55...35R
Altcode: 1994oaem.conf...35R
  No abstract at ADS

Title: A Long-Term Study of H-alpha Line Variations in FK Comae
    Berenices
Authors: Welty, Alan D.; Ramsey, Lawrence W.; Iyengar, Mrinal; Nations,
   Harold L.; Buzasi, Derek L.
Bibcode: 1993PASP..105.1427W
Altcode:
  We present observations of H-alpha V/R ratio variations in FK Comae
  Berenices obtained during several observing seasons from 1981 to
  1992. The raw H-alpha emission profile is always observed to be
  double-peaked due to the stellar absorption component. During most
  years the V/R ratio varies regularly with the period of the photometric
  light curve. The V/R periodicity is most obvious when time spans
  no longer than several stellar rotations are considered. We propose
  that the bulk of the emission component of the H-alpha line arises
  in corotating circumstellar material that may be similar to that of a
  quiescent solar prominence. The lifetime of these structures appears
  to be on the order of weeks. A weak contribution from a circumstellar
  disk is evident and chromospheric emission may also be present. The
  appearance or disappearance of circumstellar structures over periods
  longer than a few weeks, or the total absence of such structures, blurs
  the more regular variations in H-alpha seen over short timescales. Other
  more stochastic activity, such as flares, also clearly occurs. Phase
  shifts of the V/R ratio from year to year rule out the hypothesis
  that mass transfer in a close binary system is responsible for the
  V/R variations. (SECTION: Stars)

Title: The Shape of FK Comae
Authors: Welty, Alan D.; Ramsey, Lawrence W.
Bibcode: 1993AAS...18311109W
Altcode: 1993BAAS...25.1458W
  FK Comae is an evolved G giant rotating at vsin i = 164.5 +/- 2.1kms(-1)
  and exhibits a very strong Hα emission line. In addition, it has long
  been known to have other signatures of magnetic activity characteristic
  of RS CVn systems and Weak-lined T Tauri stars such as Delta V ~ 0.1
  photometric variability indicative of spots, and strong X-ray and
  UV line emission. Our recent detailed analysis of the spectrum of
  this star have turned up variations in vsin i that we attribute to
  changes in the shape of the star of order 2.5%. We present the data
  for several seasons to support this interpretation and discuss three
  possible explanations for this highly unusual observed behavior.

Title: Some Statistics for Measuring Large-Scale Structure
Authors: Brandenberger, Robert H.; Kaplan, David M.; A, Stephen; Ramsey
Bibcode: 1993astro.ph.10004B
Altcode:
  Good statistics for measuring large-scale structure in the Universe
  must be able to distinguish between different models of structure
  formation. In this paper, two and three dimensional ``counts in cell"
  statistics and a new ``discrete genus statistic" are applied to toy
  versions of several popular theories of structure formation: random
  phase cold dark matter model, cosmic string models, and global texture
  scenario. All three statistics appear quite promising in terms of
  differentiating between the models.

Title: A Remarkable FUV Flare on the Pleiades G Dwarf HZ 314
Authors: Ayers, T.; Basri, G.; Simon, T.; Stauffer, J.; Stern, R.;
   Antiochon, S.; Bookbinger, J.; Brown, A.; Doschek, G.; Linsky, J.;
   Ramsey, L.; Walter, F.
Bibcode: 1993AAS...182.4611A
Altcode: 1993BAAS...25..875A
  No abstract at ADS

Title: ROSAT X ray survey observations of active chromospheric binary
    systems and other selected sources
Authors: Ramsey, Lawrence W.
Bibcode: 1993psu..rept.....R
Altcode:
  The connection between processes that produce optical chromospheric
  activity indicators and those that produce x-rays in RS CVn binary
  systems by taking advantage of the ROSAT All-Sky Survey (RASS) results
  and our unique ground-based data set was investigated. In RS CVn
  systems, excess emission in the Ca 2 resonance (K &amp; H) and infrared
  triplet (IRT) lines and in the Balmer lines of hydrogen is generally
  cited as evidence for chromospheric activity, which is usually modeled
  as scaled up solar-type activity. X-ray emission in RS CVn systems is
  believed to arise from coronal loop structures. Results from spectra
  data obtained from RASS observations are discussed and presented.

Title: Lithium Line Variations in Weak-Lined T Tauri Stars
Authors: Patterer, Robert J.; Ramsey, Lawrence; Welty, Alan D.;
   Huenemoerder, David P.
Bibcode: 1993AJ....105.1519P
Altcode:
  We have observed seven weak-lined T Tauri stars to examine the
  effects of magnetic activity on the Li I 6707 A equivalent width
  and line profile. Six of the seven program stars were observed at
  least twice per evening on four consecutive nights. Variable Li I
  equivalent width is certainly present in two targets, which are the
  only known binaries (single-lined spectroscopic) in our sample, and
  likely in three others. The amplitude of the variability is consistent
  with previous estimates of activity effects. The variability itself
  supports hypotheses that observed spread in Li I equivalent widths
  may be explained by magnetic activity. It is unclear whether or not
  the binary nature of our two detections is significant. We find no
  indication that similarity to RS CVn systems, other than rapid rotation,
  is responsible for the variable activity detected.

Title: A Spectroscopic and Photometric Study of FK Comae in 1989
Authors: Huenemoerder, David P.; Ramsey, Lawrence W.; Buzasi, Derek
   L.; Nations, Harold L.
Bibcode: 1993ApJ...404..316H
Altcode:
  Results of an observational campaign, coordinated between visual
  photometry, optical spectroscopy, and UV spectroscopy, to elucidate
  the characteristics of FK Comae are presented. The photometry showed
  complicated but systematic behavior. Photospheric absorption lines
  were distorted by a Doppler-shifted bump caused by dark starspots
  resulting in small apparent radial velocity variations. No radial
  velocity variations characteristic of orbital motion were seen to
  a level of 3 km/s. Broad emission in H-alpha was modulated at the
  photospheric rotational amplitude, implying an origin no farther from
  the rotational axis than 1 stellar radius. The strengths of Ca II lines
  are modulated in phase with H-alpha but do not have velocity-modulated
  wings like H-alpha.

Title: The Spectroscopic Survey Telescope
Authors: Cordova, France A.; Ramsey, Lawrence W.
Bibcode: 1993ASPC...43..283C
Altcode: 1993sspp.conf..283C
  The scientific goals and technical character of the eight meter
  Spectroscopic Survey Telescope are described. The project to build this
  optical telescope in west Texas by the middle of this decade is a joint
  collaboration between The Pennsylvania State University, The University
  of Texas at Austin, and others. The strategy of this project is to limit
  the scientific mission to spectroscopy, emphasizing survey science. This
  results in an inexpensive, yet powerful facility for astronomy.

Title: A versatile fiber coupled CCD/echelle spectrograph system
    (in Instrumentation in Astronomy VI 1986)
Authors: Ramsey, L. W.; Huenemoerder, D. P.
Bibcode: 1993inas.book..195R
Altcode:
  No abstract at ADS

Title: Scrambling Properties of Optical Fibers and the Performance
    of a Double Scrambler
Authors: Hunter, Todd R.; Ramsey, Lawrence W.
Bibcode: 1992PASP..104.1244H
Altcode:
  Optical fibers have become increasingly commonplace in astronomical
  instrumentation during the past decade; especially in coupling
  telescopes to spectrographs. In addition to the astrophysical results
  there is also a growing literature on the properties of optical fibers
  as they pertain to astronomical observations but this has tended to
  emphasize transmission and focal ration degradation. This paper looks
  at the scrambling properties of optical fibers which are particularly
  important in precision radial velocity observations. We find that
  a single multimode step index fiber, such as is commonly used in
  astronomical applications, is deficient as a scrambler; that is the
  output beam has some memory of the input object position and incident
  angle. We go on to characterize a solution to this problem which is a
  prototype double scrambler using two fibers coupled by an afocal lens
  system. (SECTION: Instrumentation and Data Analysis)

Title: Eclipse Observations of RS CVn Binaries. I. A Survey for
    Extended Matter
Authors: Hall, Jeffrey C.; Ramsey, Lawrence W.
Bibcode: 1992AJ....104.1942H
Altcode:
  We survey a number of RS CVn systems to determine the frequency and
  nature of circumstellar matter in these chromospherically active
  binaries. A growing body of data suggests that large extended regions
  of cool, prominence-like matter may be a common phenomenon in these
  systems. Our targets are eclipsing systems as the established geometries
  and occultations are useful probes for such extended material. In this
  paper we discuss our methods and present the results of our survey and
  our spectroscopic phase monitoring of these systems. We find extended
  material in eight of the ten systems on our present survey.

Title: The Spectroscopic Survey Telescope: A Different Approach to
    8 Meter Class Instruments
Authors: Ramsey, L. W.
Bibcode: 1992AAS...180.2105R
Altcode: 1992BAAS...24Q.758R
  No abstract at ADS

Title: A Low-Resolution Spectrograph for Stellar Radial Velocity
    Measurements
Authors: Ratcliff, S. J.; Ramsey, L. W.
Bibcode: 1992AAS...180.0904R
Altcode: 1992BAAS...24..740R
  No abstract at ADS

Title: BF Orionis: Evidence for an Infalling Circumstellar Envelope
Authors: Welty, Alan D.; Barden, Samuel C.; Huenemoerder, David P.;
   Ramsey, Lawrence W.
Bibcode: 1992AJ....103.1673W
Altcode:
  Analysis of the optical magnitudes and Balmer lines of the Herbig Ae/Be
  star BF Orionis confirm that the object is an early to mid A-type
  star, but appears to be below the zero-age main sequence. Enhanced
  metal-line strengths (once thought to link BF Ori with the Am stars),
  line asymmetries, and radial velocities are shown to be signatures of
  an infalling circumstellar envelope. The possibility that BF Ori has
  a late-type companion is examined, and it is concluded that it does not.

Title: Optical Spectroscopy of Chromospherically Active Binary
    Systems in Conjunction with the ROSAT All-Sky Survey
Authors: Welty, A. D.; Hall, J. C.; Patterer, R. J.; Ramsey, L. W.;
   Huenemoerder, D. P.
Bibcode: 1992ASPC...26..116W
Altcode: 1992csss....7..116W
  No abstract at ADS

Title: A Study of Extended Matter in RS CVn Systems
Authors: Hall, J. C.; Ramsey, L. W.
Bibcode: 1992ASPC...26..359H
Altcode: 1992csss....7..359H
  No abstract at ADS

Title: Robotic Telescopes with Fiber-Coupled Spectrographs
Authors: Ramsey, Lawrence W.
Bibcode: 1992ASPC...34..227R
Altcode: 1992robt.proc..227R; 1992rote.proc..227R
  We address the scientific need for a Robotic Spectroscopic Telescope
  (RST) and discuss some of the issues that must be considered in the
  design of the telescope, the fiber couplings, and the spectroscopic
  instrumentation. Performance modeling based on experience with fiber
  coupled spectrographs indicates that a one-meter class telescope
  can provide the capability to carry out a wide variety of scientific
  programs, as well as most economically demonstrate the feasibility of
  the RST concept.

Title: Fk-Comae and the Evolution of Close Binaries
Authors: Huenemoerder, D. P.; Ramsey, L. W.; Buzasi, D. L.; Nations,
   H. L.
Bibcode: 1992IAUS..151..403H
Altcode:
  No abstract at ADS

Title: Short-Term Variability in the RS Canum Venaticorum System
    HR 1099
Authors: Buzasi, Derek L.; Huenemoerder, David P.; Ramsey, Lawrence W.
Bibcode: 1991PASP..103.1077B
Altcode:
  Observations of the RS CVn system HR 1099 made during the 1988 season
  are discussed. A dramatic reduction in extraphotospheric emission
  occurred on the primary during the observing period; this reduction
  is ascribed to the disappearance of a prominence on the K star. In
  addition, the system shows evidence for the process of mass transfer
  similar to those seen in the RS CVn system UX Ari.

Title: Detection of Possible p-Mode Oscillations on Procyon
Authors: Brown, Timothy M.; Gilliland, Ronald L.; Noyes, Robert W.;
   Ramsey, Lawrence W.
Bibcode: 1991ApJ...368..599B
Altcode:
  In the course of a search for solar-like oscillations in bright
  late-type stars, Doppler variability was observed in the F5 subgiant
  Procyon. The variations have frequencies within a 1.1 mHz range
  centered at 0.9 mHz, and a total rms amplitude within that range
  of 2.5 m/s. Observations of Arcturus and scattered sunlight made
  with the same equipment during the same time interval show no such
  variation, indicating that the variations seen on Procyon are of stellar
  origin. The Doppler signal seen is entirely consistent with solar-like
  p-modes on Procyon, with maximum mode amplitudes of about 50 cm/s
  and periods around 20 minutes. Several statistical tests support the
  identification for the signal with narrow-band oscillations, but none
  does so conclusively. Assuming that the signal does arise from p-modes,
  there is evidence that the frequency splitting nu(0) is 71 micro-Hz. The
  data do not permit a definite estimate of this quantity, and other
  values of nu(0) fit the observations about equally well. In order to
  clarify the sources of ambiguity in this and similar observations,
  the data acquisition, reduction, and interpretation are described.

Title: A new technique for study of radial velocity changes.
Authors: Ramsey, L.; Brown, T.; Gilliand, R.; Noyes, R.
Bibcode: 1991ASPC...20..614R
Altcode:
  No abstract at ADS

Title: Quiescent Prominences in Eclipsing RS CVns
Authors: Ramsey, Lawrence W.
Bibcode: 1991iue..prop.4022R
Altcode:
  We propose to observe two eclipsing RS CVn binaries, SS Bootis and AR
  Monocerotis, to study large extended regions which we believe to be
  responsible for much of the emission in these systems. Ground-based
  observations show attenuation of the emission from the eclipsed
  component in both systems at a point near but not in eclipse. As the
  eclipse ends, the emission level returns to its average out-of-eclipse
  value, indicating that a large, obscuring, off-limb feature on the
  eclipsing component is present. IUE LWPLo observations of the Mg II
  lines in both systems at the proper phases will provide important
  data regarding the structure of the emitting regions as well as the
  degree to which they are responsible for the emission. With combined
  optical and UV data on these systems we will be able to constrain the
  size and possibly the optical depth of these structures.

Title: Fixed Phase Observations of RS CVn Stars
Authors: Hall, J. C.; Huenemoerder, D. P.; Ramsey, L. W.; Patterer,
   R. J.; Chester, M. M.
Bibcode: 1990BAAS...22.1292H
Altcode:
  No abstract at ADS

Title: A Computer Model of Echelle Spectrograph Efficiency
Authors: Horner, S. D.; Brown, T. M.; Ramsey, L. W.
Bibcode: 1990BAAS...22.1260H
Altcode:
  No abstract at ADS

Title: Fiber-optic Echelle CCD Observations of SS Bootis
Authors: Hall, Jeffrey C.; Huenemoerder, David P.; Ramsey, Lawrence
   W.; Buzasi, Derek L.
Bibcode: 1990ApJ...358..610H
Altcode:
  The faint RS CVn system SS Bootis was observed over two seasons, and the
  most prominent surface activity indicators in this spectroscopically
  understudied object were examined. The first two Balmer lines are
  consistently strong in emission, as are the Ca II infrared triplet and
  Ca II H line; there is no significant modulation with phase in any of
  these lines. No excess emission is evident in He I D3. The ratio of
  energy emitted in H-alpha to that in H-beta is typically between three
  and six for the more active subgiant primary, and between two and five
  for the dwarf secondary. Of special interest is an excess absorption
  feature in the Balmer lines near primary eclipse in both seasons. The
  feature lies near the velocity of the secondary, and as there is no
  similar feature in secondary eclipse, it is suggested that it arises
  from obscuring material associated with the primary. From the extent
  of the feature and the system's geometry, limits were placed on the
  parameters of such material.

Title: Coordinated Optical and Ultraviolet Observations of DH Leo
Authors: Newmark, Jeffrey S.; Buzasi, Derek L.; Huenemoerder, David
   P.; Ramsey, Lawrence W.; Barden, Samuel C.; Nations, Harold L.; Seeds,
   Michael A.
Bibcode: 1990AJ....100..560N
Altcode:
  Results are reported from contemporaneous KPNO optical spectroscopy,
  IUE UV spectroscopy, and KPNO R photometry of the DH Leo triple
  system in spring 1987. The data are presented in tables, graphs,
  and spectral phase images and discussed in detail. The H-alpha,
  H-beta, H-gamma, H-delta, and Ca II H and IRT lines are found to
  have excess emission, and the phase modulation in H-alpha, H-beta,
  and Ca II is well correlated with the photometric modulation. This
  result is attributed to the combination of (1) a small amount of
  global chromospheric emission and (2) emission from plagelike regions
  associated with cool starspots. The (H-alpha)/(H-beta) ratio is found
  to be significantly lower than that in longer-period RS CVn systems.

Title: Coordinated Optical and Ultraviolet Observations of IM Pegasi
Authors: Huenemoerder, David P.; Ramsey, Lawrence W.; Buzasi, Derek L.
Bibcode: 1990ApJ...350..763H
Altcode:
  IUE spectra and optical observations of IM Peg obtained during the
  summers of 1985 and 1986 are analyzed. The modulations of the UV
  emission lines and the H-alpha, H-beta, and the CaII IR triplet (IRT)
  optical lines are examined. It is observed that: the UV emissin-line
  modulation increases as a function of height, H-alpha variability
  is related to stochastic events, H-beta displays excess absorption
  relative to a standard star, and the Ca IRT reveals a clear modulation
  with phase. It is noted that IM Peg corresponds to the solar paradigm
  used to explain RS CVn activity.

Title: The Disappearance of a Prominence on HR1099
Authors: Buzasi, D. L.; Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1990ASPC....9..233B
Altcode: 1990csss....6..233B
  No abstract at ADS

Title: Optical and Ultraviolet Spectra of Rs-Canum Stars
Authors: Ramsey, Lawrence W.
Bibcode: 1990ASPC....9..195R
Altcode: 1990csss....6..195R
  The observed phenomenology in RS CVn and related binary systems is
  considered in terms of its modeling according to solar activity by
  examining UV and optical spectroscopy. Current data are examined
  to validate the existence of cool starspots, plage, prominences, and
  flares, as well as to determine the consistency of spatial correlations
  given by these data. RS CVn stars show spots at or near the poles,
  contrasting the low latitudes of solar spots; plage appears to be
  associated with cool spots on BY Draconis-like systems; plage and
  prominences, although identified as distinct phenomena, are theorized
  to be the same event in some cases. More spectroscopic and photometric
  observations are proposed to identify the detailed structure and
  locations of spots. UV and visible data are also required to distinguish
  plage regions from flare variations as well as determine the relation of
  extended structures to starspot and plage phenomena in RS CVn systems.

Title: Evidence for Extended Material in the Eclipsing RS CVn System
    SS Bootis
Authors: Hall, J. C.; Huenemoerder, D. P.; Ramsey, L. W.; Buzasi, D. L.
Bibcode: 1990BAAS...22..739H
Altcode:
  No abstract at ADS

Title: Optical Spectroscopy of ER Vul
Authors: Newmark, J. S.; Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1990BAAS...22..739N
Altcode:
  No abstract at ADS

Title: Echelle Observations of V410 Tau
Authors: Patterer, R.; Huenemoerder, D.; Ramsey, L.; Buzasi, D.
Bibcode: 1990BAAS...22..749P
Altcode:
  No abstract at ADS

Title: Flares and Other Optical Emission Line Variations in II-Peg
Authors: Huenemoerder, David P.; Ramsey, Lawrence W.; Buzasi, Derek L.
Bibcode: 1990ASPC....9..236H
Altcode: 1990csss....6..236H
  Spectroscopic observations of II Pegasi are reported with particular
  attention given to flares observed in the He D3 emission, Balmer line
  ratios, and in comparisons of H-alpha and H-beta. A flare in progress
  was detected, and comparisons with an earlier harder flare shows that
  large flares can reach maximum intensity in optical lines after more
  than six hours. The possibility of small amplitude variations of the
  minimum emission and random emission events is set forth to describe
  the Balmer line modulation.

Title: Titanium Oxide Variations in II Pegasi
Authors: Huenemoerder, David P.; Ramsey, Lawrence W.; Buzasi, Derek L.
Bibcode: 1989AJ.....98.2264H
Altcode:
  TiO 8860 A band variations were detected in the RS CVn star II Pegasi
  during the fall of 1988. UBV photometry shows that the variations are
  correlated with the star's brightness. The TiO is stronger when the
  star is fainter. The results are used to estimate cool photospheric
  spot sizes of 2030 deg, with equivalent spectral types similar to an
  M4 to M6 star.

Title: Fiber-Optic-Echelle-CCD Spectral Monitoring of UX ARIETIS
Authors: Huenemoerder, David P.; Buzasi, Derek L.; Ramsey, Lawrence W.
Bibcode: 1989AJ.....98.1398H
Altcode:
  Results are presented on 30 fiber-optic-echelle-CCD spectra for the UX
  Ari system, covering one orbit in the spring and two orbits in the fall
  of 1987. The spectra obtained have a resolution of about 12,000 over the
  range of the Ca II H lines in the near UV to the Ca II triplet in the
  near IR, covering several activity sensitive lines. The most striking
  features observed were strong H-alpha and H-beta absorption near phase
  0.8, which were present at epochs eight months apart. The geometry of
  the system, as determined from the mass ratio, rotational velocities,
  and the assumption of synchronous rotation, gives a radius for the K
  star that is approximately filling its Roche lobe. It is suggested that
  the excess absorption seen is due to mass-transfer activity resulting
  from Roche lobe overflow of the K star and accretion onto the G star.

Title: Coordinated Observations of FK Comae
Authors: Ramsey, Lawrence W.
Bibcode: 1989iue..prop.3470R
Altcode:
  This proposal requests IUE time to obtain SWP low dispersion spectra
  during ten US2 half shifts. The target is FK Comae. The research
  goal is to obtain a complete UV and optical data set over just a few
  rotational periods of this star. In an attempt to better understand
  this peculiar object we will correlate the activity indicators in the
  visible region with those in the UV. Ground based observations will
  be obtained contemporaneously and simultaneously where possible. The
  IUE data will primarily provide information on activity in the stellar
  transition region through transitions of N V, C IV and Si IV in the SWP
  spectral region. Lines such as C II sample the high chromosphere whereas
  the ground based data will supply information on the low chromosphere
  and photosphere. Mg II data will also be obtained to supplement the
  ground based data and to provide velocity resolution within the observed
  profile. The proposed program will lead to a unique data set on this
  interesting star and will allow progress toward understanding it and
  similar systems.

Title: A Progress Report on the Spectroscopic Survey Telescope
Authors: Ramsey, L. W.; Weedman, D. W.; Ray, F. B.; Sneden, C.
Bibcode: 1988ESOC...30..119R
Altcode: 1988vlti....1..119R; 1988vltt.conf..119R
  The Penn State/University of Texas Spectroscopic Survey Telescope is
  an eight meter aperture special purpose telescope. The authors report
  here on the final configuration and progress on the optical train as
  well as the anticipated performance of the instrument.

Title: The HAO/Lowell/AFGL Solar-Stellar Spectrophotometer
Authors: Fisher, R. R.; Ramsey, L. W.; Gilliland, R. L.; Radick, R.;
   Lockwood, G. W.; Mihalas, D.
Bibcode: 1988BAAS...20..994F
Altcode:
  No abstract at ADS

Title: Radiative Transfer Modeling of Spectral Subtraction
Authors: Buzasi, D. L.; Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1988BAAS...20R.994B
Altcode:
  No abstract at ADS

Title: Fiber-Optic-Echelle-CCD Spectral Monitoring of UX Aretis
Authors: Huenemoerder, D. P.; Buzasi, D. L.; Ramsey, L. W.
Bibcode: 1988BAAS...20..993H
Altcode:
  No abstract at ADS

Title: Detection of Supergiant Variability with the HAO/Lowell/AFGL
    Solar Stellar Spectrophotometry Project(S<SUP>3</SUP>)
Authors: Ramsey, L. W.; Mihalas, D.; Radick, R.; Gilliland, R. L.;
   Lockwood, G. W.; Fisher, R.; Gallagher, J.
Bibcode: 1988BAAS...20.1012R
Altcode:
  No abstract at ADS

Title: The Stellar Observing Program of the HAO/Lowell/AFGL
    Solar-Stellar Spectrophotometry Project (S<SUP>3</SUP>)
Authors: Gilliland, R. L.; Mihalas, D.; Ramsey, L. W.; Radick, R.;
   Lockwood, G. W.
Bibcode: 1988BAAS...20..994G
Altcode:
  No abstract at ADS

Title: The Life and Times of FK Com
Authors: Nations, H. L.; Buzasi, D. L.; Huenemoerder, D. P.; Ramsey,
   L. W.
Bibcode: 1988BAAS...20Q1023N
Altcode: 1988BAAS...20Z1023N
  No abstract at ADS

Title: Detection of supergiant variability with the HAO/Lowell/AFGL
    solar-stellar spectrophotometry project (S<SUP>3</SUP>).
Authors: Mihalas, D.; Ramsey, L. W.; Radick, R.; Gilliland, R. L.;
   Lockwood, G. W.; Fisher, R.; Gallagher, J.
Bibcode: 1988BAAS...20.1012M
Altcode:
  No abstract at ADS

Title: Use of optical fibers in spectrophotometry
Authors: Ramsey, Lawrence W.
Bibcode: 1988itp..work..277R
Altcode:
  The use of single or small numbers of fiber optic fibers in astronomical
  spectroscopy with the goal of greater spectrophotometric and radial
  velocity accuracy is discussed. The properties of multimode step index
  fibers which are most important for this application are outlined,
  as are laboratory tests of currently available fibers.

Title: The Solar Observing Program of the HAO/Lowell/AFGL
    Solar-Stellar Spectrophotometry Project (S<SUP>3</SUP>)
Authors: Mihalas, D.; Radick, R.; Lockwood, G. W.; Gilliland, R. L.;
   Ramsey, L. W.; Fisher, R.; Livingston, W.; White, O. R.
Bibcode: 1988BAAS...20Q1008M
Altcode:
  No abstract at ADS

Title: Focal ratio degradation in optical fibers of astronomical
    interest.
Authors: Ramsey, Lawrence W.
Bibcode: 1988ASPC....3...26R
Altcode: 1988fopa.proc...26R
  This paper discusses the sources of the focal ratio degradation (FRD)
  of step index fused silica core optical fibers, and describes the
  measurements of FRD properties. It is concluded that, although the FRD
  does not appear to be sensitive to the large scale bending of the fiber,
  this bending might induce stress which causes microbends. It was found
  that larger core fibers appear to have better FRD characteristics than
  smaller core fibers of identical construction, and that soft buffered
  fibers have better FRD features than hard buffered fibers. The best
  f-ratios to feed typical glass-clad fibers appears to be from about
  f/3.0 to about f/7.0, depending on the fiber diameter. Finally,
  it was found that good FRD characteristics are not compatible with
  the good radial image scrambling needed for high-precision radial
  velocity observations.

Title: Use of optical fibers in spectrophotometry.
Authors: Ramsey, L. W.
Bibcode: 1988NASCP......277R
Altcode:
  The author discusses the use of a single or small numbers of fibers
  in astronomical spectroscopy with the goal of achieving greater
  spectrophotometric and radial velocity accuracy. The properties
  of multimode step index fibers which are most important for this
  application are outlined as are the laboratory tests of currently
  useful commercially available fibers.

Title: A Flare Event on the Long-Period RS Canum Venaticorum System
    IM Pegasi
Authors: Buzasi, Derek L.; Ramsey, Lawrence W.; Huenemoerder, David P.
Bibcode: 1987ApJ...322..353B
Altcode:
  The characteristics of a flare event detected on the long-period RS
  CVn system IM Pegasi are reported. The low-resolution spectrum show
  enhancements of up to a factor of five in some emission lines. All
  of the ultraviolet emission lines normally visible are enhanced
  significantly more than the normal 30 rotational modulation. Emission
  fluxes of both the quiescent and flare event are used to construct
  models of the density and temperature variation with height. These
  models reveal a downward shift of the transition region during the
  flare. Scaled models of the quiet and flaring solar outer atmosphere
  are used to estimate the filling factor of the flare event at about
  30 percent of the stellar surface. The pattern of line enhancements
  in the flare is the same as a previous event in Lambda Andromeda
  observed previously.

Title: Fiber Coupled Instrumentation for the Spectroscopic Survey
    Telescopes
Authors: Ramsey, L. W.
Bibcode: 1987BAAS...19.1098R
Altcode:
  No abstract at ADS

Title: Performance of the Penn State Fiber Optic Echelle at KPNO
Authors: Barden, S. C.; Ramsey, L. W.; Huenemoerder, D. P.; Buzasi, D.
Bibcode: 1987BAAS...19.1099B
Altcode:
  No abstract at ADS

Title: Transient Features on FK Comae
Authors: Buzasi, D. L.; Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1987BAAS...19Q1026B
Altcode: 1987BAAS...19.1026B
  No abstract at ADS

Title: CCD Echelle Observations of the Active RS CVn System II Pegasi
Authors: Huenemoerder, David P.; Ramsey, Lawrence W.
Bibcode: 1987ApJ...319..392H
Altcode:
  Optical spectra were obtained of II Peg on eight different nights in
  1984 and 1985 to assess the strength and variability of surface activity
  indicators in this very active RS CVn system. These cross-dispersed
  echelle spectra covered the range from 390 nm to 900 to 900 nm at a
  resolution of 12,000. EMission was seen in the first four Balmer lines,
  in the Ca II infrared triplet, Ca II H lines, and in one observation,
  in He I D3. The ratio of energy emitted in the H-alpha line to that
  in H-beta is similar to that in solar prominences, except during
  enhancements when the ratio decreases toward values more typical
  of solar flares. The H-alpha lines varied both in strength and in
  profile. There were slight variations in the Ca II infrared triplet
  lines. Exposure levels were too weak to assess the variations in
  H-gamma, H-delta, or Ca II H. Relative to comparison star spectra,
  the TiO bands at 896 nm and 710 nm were slightly deeper in II Peg,
  which is indicative of cool spots.

Title: Improvements in spectroscopic continuum noise with fiber-optics
    illumination of a RETICON array.
Authors: Smith, Myron A.; Graves, J. E.; Jaksha, David B.; Plymate,
   Claud L.; Ramsey, Lawrence W.
Bibcode: 1987PASP...99..654S
Altcode:
  It is shown that under certain observing conditions the pixel-to-pixel
  spectroscopic noise of a Reticon detector can be reduced somewhat
  by the uniform illumination of the pixels by a fiber-optic image
  scrambler. These gains can nearly offset the transmission losses in
  the fiber imaging system. The optical layer of the 'solar stellar
  spectrograph' at the McMath Solar Telescope is also described.

Title: Development of high stability fiber optic spectrophotometric
    systems for study of solar/stellar magnetic activity
Authors: Ramsey, Lawrence W.
Bibcode: 1987psu..reptQ....R
Altcode:
  A program to study magnetic activity cycles in solar-type stars,
  including the Sun, is described. The goal is to establish the
  relationships between a star's magnetic cycle morphology (i.e.,
  amplitude, period, shape, regularity, etc.) and its age, rotation
  rate, and if possible, differential rotation rate, for a variety
  of solar like stars. Basic empirical input will be provided for the
  construction of a viable dynamical dynamo theory for the Sun and the
  stars, leading to a deeper understanding of the ultimate origins of
  solar and stellar magnetism. Only when a realistic theory of magnetic
  field generation is available can one understand fully the physics of
  magnetic activity, which manifests itself on all temporal and spatial
  scales, from transients such as flares to long-lived structures
  such as quiescent prominences, from flux-tubes at the limit of
  resolution to complex groups of sunspots. A critical first step in
  this effort was the development of an appropriate instrument. What
  follows describes an advanced-design, special-purpose, fiber fed
  spectrograph carefully optimized to make the required observations
  with maximum efficiency. This contract designs, fabricates and tests
  the breadboard instrument.

Title: Coordinated Optical and UV Observations of the Short Period
    RS CVn System DH Leo
Authors: Ramsey, Lawrence
Bibcode: 1987iue..prop.2837R
Altcode:
  We propose to observe the short-period RS CVn system DH Leo with IUE
  to investigate the presence of "prominence-like" material surrounding
  the secondary component. Observations will be made with the SWP camera
  in low dispersion outside and during primary conjunction. If the
  chromospheric lines in the SWP region arise from the same plasma as
  H-alpha we should see decreased emission at conjunction. The behavior
  of the hotter lines (N V, Si IV, C IV) should allow us to constrain
  somewhat the location of the occulting material. The IUE observations
  will be accompanied by ground based spectroscopic and photometric
  observations to better define the state of the surface activity at
  that time.

Title: Spectroscopic monitoring of RS CVn stars at Kitt Peak using
    the Penn State Fiber Optic Echelle.
Authors: Ramsey, L. W.; Huenemoerder, D. P.; Buzasi, D. L.; Barden,
   S. C.
Bibcode: 1987LNP...291..514R
Altcode:
  No abstract at ADS

Title: Spectroscopic Monitoring of RS CVn Stars at Kitt Peak Using
    the Penn State Fiber Optic Echelle
Authors: Ramsey, Lawrence W.; Huenemoerder, David P.; Buzasi, Derek
   L.; Barden, Samuel C.
Bibcode: 1987LNP...291..515R
Altcode: 1987LNP87.291..515R; 1987csss....5..515R
  The Penn State Fiber Optic Echelle has been moved to Kitt Peak and
  works with either the coude feed telescope or 2.1 meter. It is about
  twice as efficient as the coude Camera No. 5 for similar bandpass at
  600 nm and is comparable at 400 nm using the coude feed telescope. The
  high illumination stability afforded by the fiber is a decided advantage
  where spectrophotometric and radial velocity stability are at a premium,
  as in the study of active stars. We are using this instrument to
  intensively monitor about 10 regular RS CVn systems and about six short
  period and W UMa systems for a two week period each observing semester.

Title: Hα observations of RS Canum Venaticorum stars. II. 1981
    observations for UX Arietis, HR 1099, and BD +61°1211.
Authors: Nations, Harold L.; Ramsey, Lawrence W.
Bibcode: 1986AJ.....92.1403N
Altcode:
  H-alpha line observations made during 1981 of the highly active RS
  CVn stars UX Ari, HR 1099, and BD +61 deg 1211 are presented and
  discussed. Excess H-alpha emission profiles derived by subtracting
  synthesized comparison-star spectra are analyzed to find that the UX Ari
  and HR 1099 systems differ significantly in the strength of the excess
  emission from their secondaries. Specifically, it is found that in UX
  Ari the H-alpha emission of the K subgiant completely dominates that of
  the G V secondary. In HR 1099, however, the K1 IV primary is responsible
  for 86 percent of the total emission and the G5 IV secondary 14 percent,
  with the smaller secondary showing the higher surface flux. H-alpha
  spectra from the single-lined system BD +61 deg 1211 show a strong,
  broad emission line which is variable by over a factor of 3 during
  the observational period. The data for these systems are discussed in
  terms of the L(H-alpha)/L(bol) vs log P relation for the RS CVn stars.

Title: The Spectroscopic Survey Telescope
Authors: Weedman, D.; Ramsey, L.; Ray, F.; Sneden, C.
Bibcode: 1986BAAS...18..956W
Altcode:
  No abstract at ADS

Title: An Ultraviolet Flare on the RS CVn System IM Pegasus
Authors: Ramsey, L. W.; Buzasi, D. L.
Bibcode: 1986BAAS...18..954R
Altcode:
  No abstract at ADS

Title: The Penn-State Fiber Coupled CCD / Echelle Spectrograph
Authors: Ramsey, L. W.
Bibcode: 1986tswo.work...80R
Altcode:
  The author describes a versatile echelle spectrograph which is coupled
  to their 1.6 meter telescope via an optical fiber. Observations obtained
  since winter 1985 have shown the instrument to have excellent flat-field
  and radial velocity performance properties with quite respectable
  throughput.

Title: Report of the Instrumentation Subpanel
Authors: Dunn, R.; Ramsey, L.; Smith, M. A.
Bibcode: 1986tswo.work...93D
Altcode:
  No abstract at ADS

Title: The Spectroscopic Survey Telescope
Authors: Ramsey, L. W.; Weedman, D. W.
Bibcode: 1986tswo.work..117R
Altcode:
  The authors describe the motivation for and general design of a large
  special purpose spectroscopic survey telescope (SST). The telescope
  is based on an array of 73 spherically figured segments about a
  meter in diameter with a radius of curvature of 26 meters making up
  a primary mirror with an effective aperture exceeding 7 meters. All
  tracking motions are in a lightweight focal surface system that can
  track objects for up to 40 minutes using a two element reflecting
  corrector for spherical aberration. The telescope has a fixed tilt to
  the vertical which allows access to a 48 degree strip of declination
  through an azimuth angle rotation. Instrumentation is coupled to the
  focus by means of fiber optics. Multiple object tracking over the 50
  deg<SUP>2</SUP> field is possible.

Title: The Light Curve, H-α Modulation, and Possible Prominences
    of the Short-Period Binary DH Leo
Authors: Barden, S. C.; Fried, R. E.; Ramsey, L. W.; Guinan, E. F.;
   Wacker, S. W.
Bibcode: 1986LNP...254..241B
Altcode: 1986csss....4..241B
  No abstract at ADS

Title: A versatile fiber coupled CCD/echelle spectrograph system.
Authors: Ramsey, Lawrence W.; Huenemoerder, David P.
Bibcode: 1986SPIE..627..282R
Altcode:
  A versatile echelle spectrograph capable of moderate to high
  resolution precision spectroscopy has been developed. This highly
  stable instrument is in a temperature- and humidity-controlled room,
  and is coupled to a 1.6-m telescope via an optical fiber. Moderate
  resolution spectra with near-total spectral coverage from 400-900 nm
  are done at a Quasi-Littrow focus with no anamorphic magnification. A
  200 mm f/2 camera focuses thirty-four orders of prism cross dispersed
  spectra onto a CCD. A simple grating tilt can switch the beam to a
  cross-dispersing grating and long focus cameras allowing resolutions
  up to 80,000. The high resolution beam has a more typical geometry with
  anamorphic magnification greater than one. Observations conducted since
  winter, 1985 have shown the system to have excellent photometric and
  radial velocity characteristics; it is especially suited to long term,
  high SNR monitoring programs.

Title: A CCD/Echelle Spectroscopy System for Study of Active Cool
    Stars
Authors: Ramsey, L. W.; Huenemoerder, D. P.
Bibcode: 1986LNP...254..238R
Altcode: 1986csss....4..238R
  No abstract at ADS

Title: Echelle Spectroscopy of the RS CVn System II Pegasus
Authors: Ramsey, L. W.; Huenemoerder, D. P.
Bibcode: 1985BAAS...17..880R
Altcode:
  No abstract at ADS

Title: Hα Observations of RS CVn Stars: 1981 Spectra of UX Ari,
    HR 1099, BD +61 1211 and HD 155638
Authors: Nations, H. L.; Ramsey, L. W.
Bibcode: 1985BAAS...17..754N
Altcode:
  No abstract at ADS

Title: H<SUP>α</SUP> Activity and the Light Curve of the RS Canum
    Venaticorun Star DH Leo (HD86590)
Authors: Barden, S. C.; Ramsey, L. W.; Fried, R. E.
Bibcode: 1985BAAS...17R.597B
Altcode:
  No abstract at ADS

Title: The Penn State Fiber Coupled-CCD Spectrograph System
Authors: Ramsey, L. W.; Brungardt, C.; Huenemoerder, D. P.;
   Rosenthal, S.
Bibcode: 1985BAAS...17..574R
Altcode:
  No abstract at ADS

Title: CCD-Echelle Reduction with the Charles River Super-micro
Authors: Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1985BAAS...17..575H
Altcode:
  No abstract at ADS

Title: Coordinated Observations of Rotational Modulation in Long
    Period RS CVn Systems
Authors: Ramsey, Lawrence
Bibcode: 1985iue..prop.2211R
Altcode:
  This proposal requests IUE time to obtain SWP low dispersion spectra
  during 10 US2 shifts during the Fall of 1985. The targets are all
  late G or early K giants in long period active chromosphere RS Canum
  Venaticorum binary systems. The research goal is to discern the
  spatial relationship and extent of the surface active regions in both
  the horizontal and vertical directions. Ground based observations
  will be obtained contemporaneously over the fall season. We will
  use the C IV line as the primary activity indicator in the stellar
  transition region, whereas ground based observations will supply
  information on the chromosphere and photosphere. We will particularly
  be seeking information on the relative shape and phase lead or lag
  of the transition region emission relative to the chromospheric and
  photospheric rotational phase behavior.

Title: Balmer Decrements in Active Chromosphere Stars
Authors: Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1984BAAS...16..912H
Altcode: 1984BAAS...16T.912H
  No abstract at ADS

Title: A spectroscopic study of the peculiar giant FK Comae. I. The
    radial velocity variation and its implications.
Authors: McCarthy, J. K.; Ramsey, L. W.
Bibcode: 1984ApJ...283..200M
Altcode:
  The authors present observations of the radial velocity behavior of
  the peculiar, rapidly rotating late-type giant FK Comae. Observations
  of the Na D lines in FK Comae and several well-studied radial
  velocity standards were obtained on 15 nights during late winter
  and spring 1982. Using cross-correlation techniques to search for
  variations against the standards, the authors set an upper limit of
  5 km s<SUP>-1</SUP>. The implications of this limit on models for
  FK Comae extant in the literature are discussed in detail, with the
  conclusion that models requiring accretion from a binary companion
  are inconsistent with the current data.

Title: Hydrogen-alpha observations of RS Canum Venaticorum
    stars. III. The eclipsing systems AR Lacertae and SZ Piscium.
Authors: Huenemoerder, D. P.; Ramsey, L. W.
Bibcode: 1984AJ.....89..549H
Altcode:
  The authors have spectroscopically monitored two eclipsing double-lined
  RS CVn binaries, AR Lacertae and SZ Piscium, over many orbital periods
  at the wavelength of Hα. Excess Hα emission profiles were derived by
  subtracting composite comparison spectra synthesized from observations
  of single inactive stars. AR Lac showed no excess Hα emission. SZ Psc
  was highly active with emission from the cooler stellar component. SZ
  Psc also underwent a large Hα outburst during and after which profiles
  were suggestive of a circumstellar origin.

Title: New Estimates on Rotational Velocity of FK Comae and Other
    FK Comae-Type Objects
Authors: Ramsey, L. W.; Barden, S. C.; Huenemoerder, D. H.; McGarthy,
   J. K.
Bibcode: 1984BAAS...16..511R
Altcode:
  No abstract at ADS

Title: Hydrogen alpha observations of RS Canum Venaticorum
    stars. I. II Peg.
Authors: Ramsey, L. W.; Nations, H. L.
Bibcode: 1984AJ.....89..115R
Altcode:
  The authors present observations of the active RS CVn variable II
  Peg made during the 1981 observing season. A marked change in the
  emission line behavior with phase over that observed several years ago
  is noted. In addition a unique decrease in the H-alpha emission flux
  to unprecedented sustained low levels was observed during the summer
  of 1981.

Title: The Penn State spectroscopic survey telescope
Authors: Ramsey, L. W.; Weedman, D. W.
Bibcode: 1984vlti.conf..851R
Altcode: 1984IAUCo..79..851R
  A design is presented for a telescope which is large enough to obtain
  spectra to about 20th magnitude in under 20 minutes' integration time
  and which is devoted to spectroscopic surveys in dark time to map the
  distribution of galaxies and quasars in the universe. During bright
  time the telescope will be used to monitor large numbers of G-M stars
  with high-resolution spectroscopy to search for solarlike activity. The
  instrument consists of 73 segments, each of 0.9 m diameter and 26 m
  radius of curvature. The effective aperture exceeds 7 m. The focal
  plane system can track objects for 40 minutes, and sky coverage of
  48 deg is obtained by using a fixed tilt for the primary and making
  the entire telescope and dome rotatable. The focal plane system is
  lightweight and precisely pointable because spectrographs are coupled
  to the focus by fiber optic cables.

Title: Hα Activity in the RS CVn System, SZ Psc
Authors: Huenemoerder, D. P.; Ramsey, L. W.; Barden, S. C.
Bibcode: 1983BAAS...15..663H
Altcode:
  No abstract at ADS

Title: Hα spectroscopy of the FK Comae type HD 199178: a progress
    report.
Authors: Huenemoerder, D. P.; Barden, S. C.; Ramsey, L. W.
Bibcode: 1983BAAS...15..616H
Altcode:
  No abstract at ADS

Title: New radial velocity limits for FK Comae.
Authors: McCarthy, J. K.; Ramsey, L. W.
Bibcode: 1982BAAS...14..780M
Altcode:
  No abstract at ADS

Title: Stellar analogs of solar activity
Authors: Ramsey, L. W.
Bibcode: 1982psu..rept.....R
Altcode:
  A fiber-coupled spectrograph (FSC) for moderate-resolution
  stellar observations has been designed, fabricated, and tested. The
  excellent shortand long-term stability of this instrument represents a
  significant advance in the state-of-the-art for high precision stellar
  spectrophotometry. A preliminary observational survey of the greatly
  enhanced analogs of solar activity that exist in flare stars and the
  RS CVn binaries has been performed using this instrument, and the
  starspot model for explaining the photometric variability of these
  latter stars has been verified spectroscopically.

Title: Emission-line widths in galactic nuclei.
Authors: Feldman, F. R.; Weedman, D. W.; Balzano, V. A.; Ramsey, L. W.
Bibcode: 1982ApJ...256..427F
Altcode:
  Line width measures for the forbidden O III emission lines have been
  obtained for 116 galactic nuclei with instrumental resolution of 165
  km/sec. Galaxies observed include 53 Seyfert 1 galaxies, 16 Seyfert 2
  galaxies, and 47 star-burst galaxies for which the nuclear emission
  lines are attributed to ionization by hot, short-lived stars. The
  median FWHM for the forbidden O III lines is 375 km/sec for Seyfert 1,
  510 km/sec for Seyfert 2, and 160 km/sec for star-burst nuclei. It is
  suggested that an empirical criterion for dividing Seyfert galaxies
  from other emission line galaxies is a FWHM greater than 250 km/sec for
  the forbidden O III lines. From dynamical arguments, the star-burst
  nuclei are determined to have the star formation activity restricted
  to a nuclear disk with radius less than a few hundred parsecs.

Title: BF Orionis-A Peculiar Pre-Main Sequence A Star
Authors: Barden, S. C.; Nousek, J. A.; Ramsey, L. W.
Bibcode: 1982BAAS...14..614B
Altcode:
  No abstract at ADS

Title: A flare event in the peculiar giant FK Comae.
Authors: Ramsey, L. W.; Nations, H. L.
Bibcode: 1982SAOSR.392A.225R
Altcode: 1982csss....2..225R
  Observations are presented of a very energetic flare event in the
  peculiar rapidly rotating star FK Comae. During this event on June
  18th 1981 the usual asymmetrical double peaked H alpha emission feature
  with an equivalent width (EW) approx 3-4 A changed to a broad emission
  feature with EW approx 13 A. Sixteen spectra were obtained over 2
  hours. Some changes in the emission profile are apparent on this time
  scale. The following night the enhanced emission persisted but at lower
  levels and it was substantially redshifted. This event is interpreted
  in terms of a model where material is injected into a disk co-rotating
  with the angular velocity of the stellar surface. A localized region
  of surface activity is conjectured to be the source of the event.

Title: Regular variations in the alf profile of FK Com.
Authors: Ramsey, L. W.; Nations, H. L.; Barden, S. C.
Bibcode: 1981ApJ...251L.101R
Altcode:
  A series of observations of the rapidly rotating G type giant FK
  Comae are presented. The unusually broad H-alpha profile is seen to
  vary regularly in the sense that the violet-to-red emission ratio is
  correlated with photometric phase and presumably with rotation. These
  observations are described by an excretion disk model with substantial
  density inhomogeneities driven at the angular velocity of the star by
  an imbedded magnetic field. That sufficient magnetic flux is available
  is suggested by both the high observed v sin i of about 120 km/s and
  photometric evidence of starspots.

Title: On the nature of H alf outbursts in the RS CVn binary SZ Psc.
Authors: Ramsey, L. W.; Nations, H. L.
Bibcode: 1981PASP...93..732R
Altcode:
  An H-alpha emission episode on the RS CVn binary SZ Psc was observed
  in 1979. These observations are compared with a recently reported
  1978 outburst, and both data are discussed and interpreted in terms of
  the surface phenomena or star-spot model. Bopp (1981) had attributed
  the 1978 H-alpha outburst as due to a mass-transfer or mass-loss
  event caused by the cooler primary expanding on a short-time scale
  and overfilling its Roche lobe. This interpretation appeared to be
  inconsistent with the surface phenomena model. Evidence is presented
  which supports the bizarre behavior of the H-alpha emission line as
  being due to the existence of a disk fed by flare-like eruptions. Bopp's
  1978 observations can also be explained in terms of such a model,
  only more material would be involved in that event, since its H-alpha
  emission is about twice as strong.

Title: NGC 7714 - The prototype star-burst galactic nucleus
Authors: Weedman, D. W.; Feldman, F. R.; Balzano, V. A.; Ramsey,
   L. W.; Sramek, R. A.; Wuu, C. -C.
Bibcode: 1981ApJ...248..105W
Altcode:
  New X-ray, ultraviolet (IUE), optical, and radio (VLA) observations
  are presented for the bright nucleus galaxy NGC 7714. All data are
  explainable as resulting from intense star-formation activity in
  this nucleus - a star burst. The X-ray and radio luminosities are
  explained by supernova remnants arising from the massive stars, and
  approximately 10,000 supernova remnants are required in a volume of
  280 pc radius. It is thought that NGC 7714 is typical of a significant
  class of emission-line galaxies. It is pointed out that individual
  supernovae should be observable in this, or similar nuclei, because
  they are expected to occur at rates approaching one per year.

Title: On the ionization equilibrium in late-type supergiants.
Authors: Ramsey, L. W.
Bibcode: 1981ApJ...245..984R
Altcode:
  We have studied the ionization balance in late-type supergiants of
  spectral types G5 to M2 using the Ca I 6573 A and forbidden Ca I 7324
  A lines as a probe. An increasing discrepancy is found between the
  observed and calculated line strengths setting in for an effective
  temperature less than approximately 4250 K. This is interpreted in terms
  of increased ionization relative to local thermodynamic equilibrium.

Title: Observations of the TiO 8860 band in M giants
Authors: Ramsey, L. W.
Bibcode: 1981AJ.....86..557R
Altcode:
  Observations are presented of the TiO δ(0,0) R-branch bandhead at 8860
  Å, which were obtained with the CID camera on the main spectrograph
  at the McMath solar telescope. At a spectral resolution of 0.25 Å,
  a bandhead index is defined which is calibrated as a function of
  effective temperature for spectral types K4 to M6. This feature is a
  potentially useful tool for study of surface inhomogeneities on active
  stars as well as a diagnostic for cool stellar atmospheres.

Title: Near-Infrared TiO Band Observations of RS CVn Stars
Authors: Nations, H.; Ramsey, L. W.
Bibcode: 1981BAAS...13..803N
Altcode:
  No abstract at ADS

Title: BVRI photometry of the RS CVn binary II Peg
Authors: Nations, H. L.; Ramsey, L. W.
Bibcode: 1981AJ.....86..433N
Altcode:
  BVRI photometric observations of the RS CVn binary II Peg are
  presented and interpreted in terms of the starspot model for RS CVn
  binaries. Observations were obtained in the Johnson B and Cousins VRI
  systems with a 16-in. telescope in conjunction with a single-channel
  pulse-counting photometer. The present light curves are observed to
  differ dramatically from those observed in 1977, in exhibiting two
  unequal maxima separated by approximately 0.55 in. orbital phase and
  a mean V magnitude of 7.52. When interpreted in terms of the starspot
  model, the light curves obtained indicate a temperature difference
  between the spots and the surrounding photosphere of 1100 + or - 450 K
  and 0.27 + or - 0.10 of the visible disk to be covered by the spots. The
  Barnes-Evans visual surface brightness relation is used to derive a
  minimum radius of 2.19 + 0.37 or - 0.31 solar radii for the primary,
  confirming a previous finding that the star is located considerably
  above the main sequence. It is recommended that II Peg be observed
  every season in order to determine the time evolution of the spot groups

Title: Evaluation of some fiber optical waveguides for astronomical
    instrumentation
Authors: Barden, S. C.; Ramsey, L. W.; Truax, R. J.
Bibcode: 1981PASP...93..154B
Altcode:
  Fused silica optical fibers were examined with a view toward use in
  fiber-coupled spectrographs. The emphasis of the investigation was on
  how well the input focal ratio was preserved during transmission down
  a long fiber. The best overall performance was given by the Galite
  4000 series and the Maxlight 150 micron fibers. The Valtec products
  also yielded good results when cabled so that stress could not be
  easily induced. It was found that the smaller fibers yielded better
  performance with respect to focal ratio preservation.

Title: Telescope Performance of a Fiber Coupled Spectrograph
Authors: Ramsey, L. W.; Barden, S. C.; Nations, H. L.; Truax, R. J.
Bibcode: 1980BAAS...12..836R
Altcode:
  No abstract at ADS

Title: HR 1099 and the starspot hypothesis for RS CVn binaries.
Authors: Ramsey, L. W.; Nations, H. L.
Bibcode: 1980ApJ...239L.121R
Altcode:
  Observations of the RS CVn binary HR 1099 (V711 Tau) have been
  made using the CCD camera at KPNO to test the starspot hypothesis
  spectroscopically. A TiO band system near 8860 A is shown to strengthen
  greatly at phases when starspots have been predicted to be present on
  the visible hemisphere. Data from other spectral regions support this
  result. A minimum temperature difference of 1000 K between the spot
  and photosphere is indicated.

Title: Spectrum variability in HR 8752.
Authors: Barden, S. C.; Ramsey, L. W.
Bibcode: 1980PASP...92..497B
Altcode:
  Observations in the region of H-alpha are presented for the luminous
  supergiant HR 8752. Two time scales for the variation of emission
  features are detected. Substantial changes in H-alpha appear to take
  months or years. More subtle changes can occur in a matter of days. The
  photospheric spectrum also shows evolution on both long and short time
  scales as has been noted by previous observers.

Title: H alf variability in HR 1099 and other RS CVn stars.
Authors: Nations, H. L.; Ramsey, L. W.
Bibcode: 1980AJ.....85.1086N
Altcode:
  Observations of the RS CVn stars HR 1099, UX Ari, HD 224085, AR Lac,
  and SZ Psc have been carried out with a CCD detector at KPNO to study
  the variability of the Hα line. The Hα equivalent width in HR 1099
  is shown to undergo a modulation over the orbital period of this
  spectroscopic binary with the modulation being in antiphase with the
  photometric distortion wave of the system. Profile and/or intensity
  variations of Ha with time scales of a few days are also demonstrated
  for the other systems studied here.

Title: Comparing Infrared Fluxes and Emission Line Widths for
    Galactic Nuclei
Authors: Weedman, D.; Balzano, Y.; Feldman, F.; Ramsey, L.
Bibcode: 1980BAAS...12..504W
Altcode:
  No abstract at ADS

Title: Implementation of a Fiber Coupled Spectrograph
Authors: Barden, S. C.; Ramsey, L. W.; Truax, R. J.
Bibcode: 1980BAAS...12Q.460B
Altcode:
  No abstract at ADS

Title: New BVRI Light Curves of HD 224085
Authors: Nations, H. L.; Ramsey, L. W.
Bibcode: 1980BAAS...12Q.530N
Altcode:
  No abstract at ADS

Title: A High Dispersion Temperature Index for Cool Stars
Authors: Ramsey, L. W.
Bibcode: 1980BAAS...12..527R
Altcode:
  No abstract at ADS

Title: Spectroscopic Evidence for Starspots on HR1099
Authors: Ramsey, L. W.; Nations, H. L.
Bibcode: 1980SAOSR.389...97R
Altcode: 1980csss....1...97R
  No abstract at ADS

Title: HR 8752
Authors: Barden, S.; Ramsey, L. W.
Bibcode: 1980IAUC.3446....1B
Altcode:
  S. Barden and L. W. Ramsey, Department of Astronomy, Pennsylvania
  State University, write: "SIT spectra (dispersion 0.15 x 10**-6)
  obtained with the eche1le spectrograph on the 1.6-m telescope indicate
  a rapid change in the emission-line spectrum of HR 8752. A spectrum
  obtained on Jan. 8.00 UT shows conspicuous Ca I 657.2-nm and Fe I
  657.4-nm emission. About 48 hr later (Jan. 9.95 UT) the Ca I emission
  was entirely absent. More subtle changes were also apparent in the
  H-alpha profile."

Title: Observations of Emission-Line Galaxies
Authors: Feldman, F.; Balzano, V.; Ramsey, L.; Weedman, D.
Bibcode: 1979BAAS...11..637F
Altcode:
  No abstract at ADS

Title: Variable mass loss in the metal deficient giant HDE 232078.
Authors: Ramsey, L. W.
Bibcode: 1979PASP...91..252R
Altcode:
  High-dispersion echelle spectra taken of the metal-deficient red
  giant HDE 232078 indicate that the mass loss rate of this star is
  highly variable. The time scale of the variability and the rate of
  mass loss is similar to Population I objects of similar temperature
  and luminosity. The nature of the variability also calls into question
  previous conclusions which indicate that the mass loss rate of globular
  cluster giants is independent of metallicity.

Title: Limits on the short-period variability of the Halpha emission
    in AD Leo.
Authors: Ramsey, L. W.
Bibcode: 1979AJ.....84..413R
Altcode:
  High-time-resolution SIT spectra of the flare star AD Leo are
  analyzed in an effort to detect any short-period variation that might
  be present. Upper limits are set on the magnitude of any variation
  down to a time scale of 5 min. No significant short-term variation was
  observed at the 2-sigma level of + or - 12%. Variation of nightly means
  on a longer time scale is clearly evident in excess of a 2-sigma level.

Title: Ionization Equilibrium in Bright Supergiants
Authors: Ramsey, L. W.; Balzano, V.
Bibcode: 1978BAAS...10..682R
Altcode:
  No abstract at ADS

Title: An Economical Cassegrain High Dispersion Spectrophotometry
    System.
Authors: Ramsey, L. W.
Bibcode: 1978BAAS...10..451R
Altcode:
  No abstract at ADS

Title: Observed departures from LTE ionization equilibrium in
    late-type giants.
Authors: Ramsey, L. W.
Bibcode: 1977ApJ...215..827R
Altcode:
  Photoelectric scans of the Ca I line at 6572 A and the forbidden
  Ca II transition at 7323 A are studied in the K giant alpha Tau,
  the M supergiant alpha Ori, and the M giants beta And, alpha Cet,
  mu Gem, and beta Peg. The relative strengths of these lines are
  shown to be indicative of the ratio of the relative number densities
  of the neutral and ionized species in the photosphere. The analysis
  indicates an overionization relative to LTE in qualitative agreement
  with the theoretical calculations of Auman and Woodrow for the K and
  M giants. The M supergiant alpha Ori exhibits a large overionization
  relative to LTE.

Title: A semiempirical atmosphere for alpha Tauri from neutral
    iron lines.
Authors: Ramsey, L. W.
Bibcode: 1977ApJ...215..603R
Altcode:
  A semiempirical model photosphere is constructed for the K5 III star
  Alpha Tau. The technique employed is based on measurements of the
  central fluxes in a series of lines in multiplets. Observations of four
  multiplets having a range in excitation potential yield the excitation
  temperature as a function of the optical depth in a reference line. If
  the temperature structure of an assumed starting model is changed
  to force agreement between the observed and predicted line source
  functions under the assumption that excitation and electron kinetic
  temperatures are equal, the final semiempirical model is cooler by
  150 K in the outer layers and warmer by 150 K in deeper layers than
  the theoretical model with the parameters adopted for Alpha Tau.

Title: Spectrophotometry of cool angular-diameter stars.
Authors: Honeycutt, R. K.; Ramsey, L. W.; Warren, W. H., Jr.; Ridgway,
   S. T.
Bibcode: 1977ApJ...215..584H
Altcode:
  Wide-band photometry and spectrophotometric scans are combined to
  obtain incident flux curves for 26 late-type stars. The wavelength
  range covered for most stars is from 0.4 to 3.0 microns with a typical
  resolution of approximately 200. Nineteen of these stars have published
  angular diameters, so that the emergent flux may be computed from the
  incident flux.

Title: Emission Line Variability of AD Leo in the Non-Flaring State.
Authors: Ramsey, L. W.
Bibcode: 1977BAAS....9..311R
Altcode:
  No abstract at ADS

Title: High dispersion spectroscopy of quiescent prominences. II:
    Vertical structure of the line-of-sight velocity field.
Authors: Ramsey, L. W.
Bibcode: 1977SoPh...51..307R
Altcode:
  A systematic study of the internal horizontal (line-of-sight) motions
  of quiescent prominences which were observed at the limb has been made
  by using fourier techniques to analyse the shift of the Ca II K line
  as a function of height above the limb. The results indicate that a
  characteristic size for the velocity elements is present in ∼70%
  of the 13 prominences studied. This size of ∼4700 km is attributed
  to Alfvén waves induced by horizontal convective motions in the
  photosphere as previously suggested by Malville. The qualitative aspects
  of the observations are described by a simple model which is based on
  this hypothesis.

Title: An Observational Study of the Physical Conditions in Red
    Giant Atmospheres.
Authors: Ramsey, L. W.
Bibcode: 1976PhDT.........6R
Altcode:
  The temperature structure and ionization balance in the atmospheres
  of red giant stars was investigated. Particular attention was given
  to the giant star Aldebaran (K5 III). The observational basis for all
  studies was moderate to high resolution photoelectric spectrophotometry
  of various atomic lines. A technique was developed to obtain the run
  of excitation temperature (Texc) with height in a stellar atmosphere
  from the central fluxes of atomic lines in a single multiplet. Source
  function equality for all lines in a multiplet and the dominance
  of the line over the continuous opacity were assumed. A test of the
  method for the sun using lines in Fe I multiplet (553) yielded good
  agreement with independently determined solar model atmospheres.

Title: Observed Departures from LTE Ionization Equilibrium in
    Cool Giants
Authors: Ramsey, L. W.
Bibcode: 1976BAAS....8Q.308R
Altcode:
  No abstract at ADS

Title: A test of solar atmospheric structure.
Authors: Ramsey, L. W.
Bibcode: 1976BAAS....8Q.293R
Altcode:
  No abstract at ADS

Title: A Method for Empirical Determination of Stellar Atmospheric
    Structure
Authors: Ramsey, L. W.; Johnson, H. R.
Bibcode: 1975SoPh...45....3R
Altcode:
  A technique for obtaining information on the temperature structure of a
  stellar atmosphere from spectral line data where only flux observations
  are available is discussed. The direct inversion of the flux integral
  to obtain the line source function can be circumvented by making the
  physically plausible assumptions of (1) source function equality in
  a multiplet and (2) the dominance of line absorption over continuum
  absorption at line center. Consistency of the technique is demonstrated
  by treating a synthetic spectrum as input data and attempting to recover
  the temperature structure of the input atmosphere. Using high quality
  solar spectrum scans obtained from K.P.N.O. we demonstrate the accuracy
  of source function equality for several Fe I multiplets and use one
  of these multiplets to obtain an empirical outer atmosphere for the
  Sun. Our empirical atmosphere agrees well with current solar models.

Title: On the Spatial Structure of Prominence Velocity Fields
Authors: Ramsey, L. W.
Bibcode: 1975BAAS....7Q.524R
Altcode:
  No abstract at ADS

Title: Macroturbulence broadening of solar lines with implications
    for stellar studies.
Authors: Evans, J. C.; Ramsey, L. W.; Testerman, L.
Bibcode: 1975A&A....42..237E
Altcode:
  This paper reports results of numerical studies of macroturbulence
  broadening on solar LTE intensity profiles with a view toward applying
  the results toward other solar-type stars. The results are compared
  for five different velocity models with spatially and temporally
  averaged center-to-limb observations. The comparisons are made through
  the curve of the line-width correlation and through the curve of the
  line-shape diagram. For mildly saturated lines (about 120 mA), the
  solar macrovelocities are the most important of the velocity scale
  sizes in determining the shape of the line core. The unsaturated weak
  lines and the curve of the line-width correlation do not discriminate
  between the two scale sizes of broadening, as suggested by other
  studies. High-accuracy photoelectric data for Procyon used in the curve
  of the line-shape indicates that macroturbulence broadening dominates
  and that the microturbulence component is about 1 km/s.

Title: High-resolution profiles of sodium and potassium lines in
    Alpha Orionis.
Authors: Goldberg, L.; Ramsey, L.; Testerman, L.; Carbon, D.
Bibcode: 1975ApJ...199..427G
Altcode:
  Profiles of the K I resonance line at 7698.98 A and of the D1
  and D2 lines of Nai in the spectrum of a Ori have been recorded
  photoelectrically using the main beam of the McMath solar telescope
  at KPNO. The Na lines were observed in the fourth order of the
  spectrograph and the K iline in the third order, providing a resolving
  power of approximately 50 mA. The observed profiles are consistent with
  a model in which radiation from the stellar photo sphere is scattered
  and reemitted by an expanding envelope or envelopes of radius large
  compared with that of the photosphere. Each blueshifted absorption
  core appears to consist of two components of approximately the same
  intensity. The first has a heliocentric radial velocity of + 11-13 km ,
  which agrees very well with measurements of other resonance lines by
  other observers, whereas the second is in the range + 6 km 1 and appears
  not to have been detected previously. Subject headings: circumstellar
  shells - late-type stars - stellar winds - stars, individual

Title: High Resolution Profiles of Sodium and Potassium Lines in
    α Orionis.
Authors: Goldberg, L.; Ramsey, L.; Testerman, L.; Carbon, D.
Bibcode: 1975BAAS....7..233G
Altcode:
  No abstract at ADS

Title: Atmospheric Structure from Spectral Line Intensities.
Authors: Ramsey, L. W.; Johnson, H. R.
Bibcode: 1975BAAS....7..257R
Altcode:
  No abstract at ADS

Title: Formation of the Luminosity-Sensitive 0 I Multiplet at 7774 A
Authors: Johnson, H. R.; Milkey, R. W.; Ramsey, L. W.
Bibcode: 1974ApJ...187..147J
Altcode:
  We have calculated line profiles and equivalent widths for the 7774 A
  multiplet of 0 i for model atmospheres in the range = K for surface
  gravities in the range log g = 4. .0. A kinetic equilibrium (KE)
  treatment of line formation can partially account for the observed
  luminosity sensitivity of these lines and considerably modifies the
  derived microturbulent broadening parameter. Line profiles obtained
  from KE line-formation theory are much deeper than LTE profiles, and
  we present new observations of Canopus (F0 Ib) to verify the essential
  correctness of our treatment. Subject headings: atmospheres, stellar -
  line formation - spectra, infrared

Title: Telluric lines in the vicinity of λ5250 and λ6562å
Authors: Livingston, W.; Ramsey, L.
Bibcode: 1973SoPh...31..317L
Altcode:
  No abstract at ADS

Title: The San Manuel Effect -- A Progress Report
Authors: Livingston, W.; Ramsey, L.
Bibcode: 1973BAAS....5R.276L
Altcode:
  No abstract at ADS

Title: A program for monitoring the abundances of atmospheric
    constituents using the McMath infrared spectrograph.
Authors: Hall, D. N.; Ramsey, L. W.
Bibcode: 1973PASP...85Q.532H
Altcode:
  No abstract at ADS

Title: Line Broadening by Macroturbulence.
Authors: Evans, J. C.; Ramsey, L. W.; Gray, D. F.
Bibcode: 1972BAAS....4..333E
Altcode:
  No abstract at ADS

