The GALAH survey : relative throughputs of the 2dF fibre positioner and the HERMES spectrograph from stellar targets

Jeffrey D. Simpson, G. M. De Silva, J. Bland-Hawthorn, K. C. Freeman, S. L. Martell, Katharine J. Schlesinger, Sanjib Sharma, D. B. Zucker, T. Zwitter, J. Kos, Borja Anguiano, David M. Nataf, Warren Reid, Robert A. Wittenmyer

Research output: Contribution to journalArticlepeer-review

Abstract

We present an analysis of the relative throughputs of the 3.9-m Anglo-Australian Telescope's 2dF/HERMES (High Efficiency and Resolution Multi-Element Spectrograph) system, based upon spectra acquired during the first two years of the Galactic Archaeology with HERMES survey. Averaged spectral fluxes of stars were compared to their photometry to determine the relative throughputs of fibres for a range of fibre position and atmospheric conditions. We find that overall the throughputs of the 771 usable fibres have been stable over the first two years of its operation. About 2.5 per cent of fibres have throughputs much lower than the average. There are also a number of yet unexplained variations between the HERMES bandpasses, and mechanically and optically linked fibre groups known as retractors or slitlets related to regions of the focal plane. These findings do not impact the science that HERMES will produce.
Original languageEnglish
Pages (from-to)1069-1081
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume459
Issue number1
DOIs
Publication statusPublished - 2016

Keywords

  • astronomical spectroscopy
  • optical fibers
  • spectrograph
  • spectroscopic techniques

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