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

A. Szentgyorgyi, A. Frebel, G. Furész, 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. McCrackenM. Ordway, D. Plummer, W. Podgorski, D. Weaver

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

32 Scopus citations

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. G-CLEF 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.

Original languageEnglish
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy IV
DOIs
StatePublished - 2012
Externally publishedYes
EventGround-Based and Airborne Instrumentation for Astronomy IV - Amsterdam, Netherlands
Duration: 1 Jul 20126 Jul 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume8446
ISSN (Print)0277-786X

Conference

ConferenceGround-Based and Airborne Instrumentation for Astronomy IV
Country/TerritoryNetherlands
CityAmsterdam
Period1/07/126/07/12

Keywords

  • Echelle spectrograph
  • Exoplanets
  • G-CLEF
  • GMT
  • High dispersion spectroscopy
  • Precision radial velocity

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