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Proceedings Paper

LRS2: the new facility low resolution integral field spectrograph for the Hobby-Eberly telescope
Author(s): Taylor S. Chonis; Gary J. Hill; Hanshin Lee; Sarah E. Tuttle; Brian L. Vattiat
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Paper Abstract

The second generation Low Resolution Spectrograph (LRS2) is a new facility instrument for the Hobby-Eberly Telescope (HET). Based on the design of the Visible Integral-field Replicable Unit Spectrograph (VIRUS), which is the new flagship instrument for carrying out the HET Dark Energy Experiment (HETDEX), LRS2 provides integral field spectroscopy for a seeing-limited field of 12" x 6". For LRS2, the replicable design of VIRUS has been leveraged to gain broad wavelength coverage from 370 nm to 1.0 μm, spread between two fiber-fed dual- channel spectrographs, each of which can operate as an independent instrument. The blue spectrograph, LRS2-B, covers 370 λ (nm) ≤ 470 and 460 ≤ λ (nm) ≤ 700 at fixed resolving powers of R = λ/δλ ≈ 1900 and 1100, respectively, while the red spectrograph, LRS2-R, covers 650 ≤ λ (nm) ≤ 842 and 818 ≤ λ (nm) ≤ 1050 with both of its channels having R ≈ 1800. In this paper, we present a detailed description of the instrument’s design in which we focus on the departures from the basic VIRUS framework. The primary modifications include the fore-optics that are used to feed the fiber integral field units at unity fill-factor, the cameras’ correcting optics and detectors, and the volume phase holographic grisms. We also present a model of the instrument’s sensitivity and a description of specific science cases that have driven the design of LRS2, including systematically studying the spatially resolved properties of extended Lyα blobs at 2 < z < 3. LRS2 will provide a powerful spectroscopic follow-up platform for large surveys such as HETDEX.

Paper Details

Date Published: 8 July 2014
PDF: 26 pages
Proc. SPIE 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91470A (8 July 2014); doi: 10.1117/12.2056005
Show Author Affiliations
Taylor S. Chonis, The Univ. of Texas at Austin (United States)
Gary J. Hill, The Univ. of Texas at Austin (United States)
Hanshin Lee, The Univ. of Texas at Austin (United States)
Sarah E. Tuttle, The Univ. of Texas at Austin (United States)
Brian L. Vattiat, The Univ. of Texas at Austin (United States)

Published in SPIE Proceedings Vol. 9147:
Ground-based and Airborne Instrumentation for Astronomy V
Suzanne K. Ramsay; Ian S. McLean; Hideki Takami, Editor(s)

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