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Proceedings Paper

The GMT-CfA, Carnegie, Catolica, Chicago Large Earth Finder (G-CLEF): a general purpose optical echelle spectrograph for the GMT with precision radial velocity capability
Author(s): A. Szentgyorgyi; A. Frebel; G. Furesz; E. Hertz; T. Norton; J. Bean; H. Bergner; J. Crane; J. Evans; I. Evans; T. Gauron; A. Jordán; S. Park; A. Uomoto; S. Barnes; W. Davis; M. Eisenhower; H. Epps; D. Guzman; K. McCracken; M. Ordway; D. Plummer; W. Podgorski; D. Weaver
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Paper Abstract

The GMT-CfA, Carnegie, Catolica, Chicago Large Earth Finder (G-CLEF) is a fiber fed, optical echelle spectrograph that has undergone conceptual design for consideration as a first light instrument at the Giant Magellan Telescope. GCLEF has been designed to be a general-purpose echelle spectrograph with precision radial velocity (PRV) capability. We have defined the performance envelope of G-CLEF to address several of the highest science priorities in the Decadal Survey1. The spectrograph optical design is an asymmetric, two-arm, white pupil design. The asymmetric white pupil design is adopted to minimize the size of the refractive camera lenses. The spectrograph beam is nominally 300 mm, reduced to 200 mm after dispersion by the R4 echelle grating. The peak efficiency of the spectrograph is >35% and the passband is 3500-9500Å. The spectrograph is primarily fed with three sets of fibers to enable three observing modes: High-Throughput, Precision-Abundance and PRV. The respective resolving powers of these modes are R~ 25,000, 40,000 and 120,000. We also anticipate having an R~40,000 Multi-object Spectroscopy mode with a multiplex of ~40 fibers. In PRV mode, each of the seven 8.4m GMT primary mirror sub-apertures feeds an individual fiber, which is scrambled after pupil-slicing. The goal radial velocity precision of G-CLEF is ∂V <10 cm/sec radial. In this paper, we provide a flowdown from fiducial science programs to design parameters. We discuss the optomechanical, electrical, structural and thermal design and present a roadmap to first light at the GMT.

Paper Details

Date Published: 5 October 2012
PDF: 15 pages
Proc. SPIE 8446, Ground-based and Airborne Instrumentation for Astronomy IV, 84461H (5 October 2012); doi: 10.1117/12.924957
Show Author Affiliations
A. Szentgyorgyi, Harvard-Smithsonian Ctr. for Astrophysics (United States)
A. Frebel, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (United States)
G. Furesz, Harvard-Smithsonian Ctr. for Astrophysics (United States)
E. Hertz, Harvard-Smithsonian Ctr. for Astrophysics (United States)
T. Norton, Harvard-Smithsonian Ctr. for Astrophysics (United States)
J. Bean, The Univ. of Chicago (United States)
H. Bergner, Harvard-Smithsonian Ctr. for Astrophysics (United States)
J. Crane, Carnegie Observatories (United States)
J. Evans, Harvard-Smithsonian Ctr. for Astrophysics (United States)
I. Evans, Harvard-Smithsonian Ctr. for Astrophysics (United States)
T. Gauron, Harvard-Smithsonian Ctr. for Astrophysics (United States)
A. Jordán, Pontificia Univ. Católica de Chile (Chile)
S. Park, Harvard-Smithsonian Ctr. for Astrophysics (United States)
A. Uomoto, Carnegie Observatories (United States)
S. Barnes, Stuart Barnes Optical Design (New Zealand)
W. Davis, Harvard-Smithsonian Ctr. for Astrophysics (United States)
M. Eisenhower, Harvard-Smithsonian Ctr. for Astrophysics (United States)
H. Epps, UCO/Lick Observatory (United States)
D. Guzman, Pontificia Univ. Católica de Chile (Chile)
K. McCracken, Harvard-Smithsonian Ctr. for Astrophysics (United States)
M. Ordway, Harvard-Smithsonian Ctr. for Astrophysics (United States)
D. Plummer, Harvard-Smithsonian Ctr. for Astrophysics (United States)
W. Podgorski, Harvard-Smithsonian Ctr. for Astrophysics (United States)
D. Weaver, Harvard-Smithsonian Ctr. for Astrophysics (United States)


Published in SPIE Proceedings Vol. 8446:
Ground-based and Airborne Instrumentation for Astronomy IV
Ian S. McLean; Suzanne K. Ramsay; Hideki Takami, Editor(s)

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