SSG Workshop 경희대 김은빈 김민배 천경원 The GMT-CfA, Carnagie, Catolica, Chicago Large Earth Finder (G-CLEF)

A fiber fed, optical echelle spectrograph Precision radial velocity capability (PRV): dV<10cm/sec Observation mode : High- Throughput (HT), Precision- Abundance (PA), and Precision Radial Velocity (PRV) Respective resolving powers : R~25,000, 40,000 and 120,000 R~40,000 multi-object spectroscopy mode with a multiplex of ~40 fibers * Collaboration : Smithsonian Astrophysical Observatory, Pontificia Universidad Catolica de Chile, University of Chicago, Harvard University, Observatories of the Carnegie Institute of Washington G-CLEF

SCIENTIFIC GOAL Science GoalRequired Perfomance Parameter Abundance studies Detection and census of metal poor stars High resolution Extended blue response to 3500 A High z IGM and ISM/Gamma Ray Burst Rapid instrument changeover Extended red response Exoearth science Very high resolution Long term wavelength stability Detailed chemical composition beyond the Local Group Long slit length for multi object capability

G-CLEF SYSTEM DESIGN

G-CLEF OPTICAL DESIGN G-CLEF Spectrograph optical layout

G-CLEF OPTICAL DESIGN G-CLEF Spectrograph optical design parameters

G-CLEF OPTICAL DESIGN G-CLEF echellograms

G-CLEF OPTICAL DESIGN Efficiency of the spectrograph

The design of the G-CLEF spectrograph 1.The stability requirements imposed by the goal of achieving the highest possible radial velocity precision(RVP) 2.Arriving at a design for the aperture of the largest optical telescope in the world with an affordable cost envelope. THERMO-MECHANICAL DESIGN

Schematic of G-CLEF thermal enclosure design THERMO-MECHANICAL DESIGN

Mechanical design of the G-CLEF spectrograph and vacuum enclosure THERMO-MECHANICAL DESIGN

The mechanical design of the blue camera THERMO-MECHANICAL DESIGN

SCHEDULE

REFERENCES  Szentgyorgyi, A. et al  k-gmt.kasi.re.kr/html/GMT/  kasi.re.kr/event/ _K- GMT_Summer_School/GMT_Instruments-spec.pdf 