First light results from the High Efficiency and Resolution Multi-Element Spectrograph at the Anglo-Australian Telescope

Andrew Sheinis, Borja Anguiano, Martin Asplund, Carlos Bacigalupo, S. Barden, Michael Birchall, Joss Bland-Hawthorn, J. Brzeski, Russell Cannon, Daniela Carollo, S. Case, A. Casey, V. Churilov, C. Warrick, R. Dean, G. De Silva, V. D'Orazi, Ly Duong, T. Farrell, Kristin Fiegert

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The High Efficiency and Resolution Multi Element Spectrograph, HERMES, is a facility-class opticalspectrograph for the Anglo-Australian Telescope (AAT). It is designed primarily for Galactic Archaeology, the firstmajor attempt to create a detailed understanding of galaxy formation and evolution by studying the history of ourown galaxy, the Milky Way. The goal of the GALAH survey is to reconstruct the mass assembly history of theMilky Way through a detailed chemical abundance study of one million stars. The spectrograph is based atthe AAT and is fed by the existing 2dF robotic fiber positioning system. The spectrograph uses volumephase holographic gratings to achieve a spectral resolving power of 28,000 in standard mode and also providesa high-resolution mode ranging between 40,000 and 50,000 using a slit mask. The GALAH survey requiresan SNR greater than 100 for a star brightness of V = 14 in an exposure time of one hour. The total spectralcoverage of the four channels is about 100 nm between 370 and 1000 nm for up to 392 simultaneous targetswithin the 2-degree field of view. HERMES has been commissioned over three runs, during bright time inOctober, November, and December 2013, in parallel with the beginning of the GALAH pilot survey, which startedin November 2013. We present the first-light results from the commissioning run and the beginning of the GALAHsurvey, including performance results such as throughput and resolution, as well as instrument reliability.
Original languageEnglish
Article number035002
Number of pages18
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Issue number3
Publication statusPublished - 1 Jul 2015
Externally publishedYes

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