LRS2: a new low-resolution spectrograph for the Hobby-Eberly Telescope

In the era of the Hobby-Eberly Telescope (HET) Wide-Field Upgrade (WFU), the current Low-Resolution Spectrograph (LRS) will be replaced with a more capable red-optimized fiber instrument, called LRS2. This new spectrograph will be based on the Visible Integral-field Replicable Unit Spectrograph (VIRUS) that was designed to be easily adapted to a wide range of spectral resolutions, and wavelength ranges. The current snapshot of LRS2, fed by a 7x12 sq. arcsec fiber integral-field unit (IFU), covers 350-1100 nm, simultaneously at a fixed resolving power R~1800, with the wavelength range split into two pairs of spectrographs, one for the blue to red wavelength range (350-630 nm) and the other for the red and far-red range (630-1100 nm). These units are designated LRS2-B and LRS2-R, respectively. Only minimal modification from the base VIRUS design in gratings (for both pairs) and in the detector (for the red pair only) is required. In addition to this flexibility, the generic nature and massively replicable characteristic of the instrument can allow us to adapt the instrument to a wide range of not only telescope diameters (1 m ~ 40 m), but also observing modes (single to multiple objects). We discuss the current snapshot of the LRS2 design.

[1]  Ulrich Hopp,et al.  FIRST-YEAR SPECTROSCOPY FOR THE SLOAN DIGITAL SKY SURVEY-II SUPERNOVA SURVEY , 2008, 0802.3220.

[2]  Phillip J. MacQueen,et al.  B2 0902+34: A COLLAPSING PROTOGIANT ELLIPTICAL GALAXY AT z = 3.4 , 2008, 0812.1333.

[3]  R. A. Gutermuth,et al.  The Disk Population of the Chamaeleon I Star-forming Region , 2008, 0803.1019.

[4]  Kevin Xu,et al.  THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY: COMPARISON OF ULTRAVIOLET AND FAR-INFRARED PROPERTIES , 2010, 1004.0985.

[5]  Hanshin Lee,et al.  Visible Integral-field Replicable Unit Spectrograph (VIRUS) optical tolerance , 2010, Astronomical Telescopes + Instrumentation.

[6]  Phillip J. MacQueen,et al.  The cryogenic system for the VIRUS array of spectrographs on the Hobby-Eberly Telescope , 2008, Astronomical Telescopes + Instrumentation.

[7]  Gary J. Hill,et al.  The TOOT survey: status and early results , 2003, astro-ph/0301441.

[8]  K. L. Luhman.  The Spatial Distribution of Brown Dwarfs in Taurus , 2006 .

[9]  Phillip J. MacQueen,et al.  Hobby-Eberly Telescope low-resolution spectrograph , 1998, Astronomical Telescopes and Instrumentation.

[10]  L. Hartmann,et al.  Measuring Accretion in Young Substellar Objects: Approaching the Planetary Mass Regime , 2005, astro-ph/0502023.

[11]  Neta A. Bahcall,et al.  Discovery of a Pair of z = 4.25 Quasars from the Sloan Digital Sky Survey , 2000, astro-ph/0008401.

[12]  James Liebert,et al.  Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field , 2006, astro-ph/0609648.

[13]  Andreas Kelz a,et al.  Prototype development of the Integral-Field unit for VIRUS , 2006 .

[14]  Subhanjoy Mohanty,et al.  The T Tauri Phase Down to Nearly Planetary Masses: Echelle Spectra of 82 Very Low Mass Stars and Brown Dwarfs , 2005, astro-ph/0502155.

[15]  Gary J. Hill,et al.  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* , 2000 .

[16]  Walter Stuermer,et al.  Characterization of DECam focal plane detectors , 2008, Astronomical Telescopes + Instrumentation.

[17]  Austin,et al.  GRB 021004: a Massive Progenitor Star Surrounded by Shells , 2002 .

[18]  David G. Monet,et al.  Dwarfs Cooler than “M”: The Definition of Spectral Type “L” Using Discoveries from the 2-Micron All-Sky Survey (2MASS) , 1999 .

[19]  Thierry Forveille,et al.  Four Quasars above Redshift 6 Discovered by the Canada-France High-z Quasar Survey , 2007, 0706.0914.

[20]  V. Narayanan,et al.  A Survey of z > 5.7 Quasars in the Sloan Digital Sky Survey. II. Discovery of Three Additional Quasars at z > 6 , 2003, astro-ph/0301135.

[21]  Todd J. Henry,et al.  A Standard Stellar Spectral Sequence in the Red/Near-Infrared: Classes K5 to M9 , 1991 .

[22]  E. Mazets,et al.  Broadband observations of the naked-eye γ-ray burst GRB 080319B , 2008, Nature.

[23]  I. Hook,et al.  Integral Field Spectroscopy with the Gemini Multiobject Spectrograph.I. Design, Construction, and Testing , 2002 .

[24]  J. Kaplan,et al.  THE SLOAN DIGITAL SKY SURVEY-II SUPERNOVA SURVEY: TECHNICAL SUMMARY , 2007, 0708.2749.

[25]  Stuart I. Barnes,et al.  Present and future instrumentation for the Hobby-Eberly Telescope , 2008, Astronomical Telescopes + Instrumentation.

[26]  E. O. Ofek,et al.  Multiwavelength Observations of GRB 050820A: An Exceptionally Energetic Event Followed from Start to Finish , 2006, astro-ph/0608183.

[27]  K. Cruz,et al.  AN INFRARED/X-RAY SURVEY FOR NEW MEMBERS OF THE TAURUS STAR-FORMING REGION , 2009, 0911.5451.

[28]  S. Bracker,et al.  A Survey for New Members of Taurus with the Spitzer Space Telescope , 2006 .

[29]  Andreas Kelz,et al.  Production-line assembly of 150+ VIRUS spectrographs , 2010, Astronomical Telescopes + Instrumentation.

[30]  Ralf Bender,et al.  VIRUS: a massively replicated 33k fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope , 2010, Astronomical Telescopes + Instrumentation.

[31]  Andreas Kelz,et al.  Design, construction, and performance of VIRUS-P: the prototype of a highly replicated integral-field spectrograph for HET , 2008, Astronomical Telescopes + Instrumentation.

[32]  Hanshin Lee,et al.  Current status of the Hobby-Eberly Telescope wide field upgrade , 2010, Other Conferences.

[33]  Mark Lacy,et al.  Two 100-Mpc-scale structures in the three-dimensional distribution of radio galaxies and their implications , 2003 .