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The GALAH survey: the data reduction pipeline.

Authors :
Kos, Janez
Jane Lin
Zwitter, Tomaž
Žerjal, Maruška
Sharma, Sanjib
Bland-Hawthorn, Joss
Asplund, Martin
Casey, Andrew R.
De Silva, Gayandhi M.
Freeman, Ken C.
Martell, Sarah L.
Simpson, Jeffrey D.
Schlesinger, Katharine J.
Zucker, Daniel
Anguiano, Borja
Bacigalupo, Carlos
Bedding, Timothy R.
Betters, Christopher
Da Costa, Gary
Ly Duong
Source :
Monthly Notices of the Royal Astronomical Society. 1/21/2017, Vol. 464 Issue 3, p1259-1281. 23p.
Publication Year :
2017

Abstract

We present the data reduction procedures being used by the GALactic Archeology with Hermes (GALAH) survey, carried out with the HERMES fibre-fed, multi-object spectrograph on the 3.9-m Anglo-Australian Telescope. GALAH is a unique survey, targeting 1 million stars brighter than magnitude V = 14 at a resolution of 28 000 with a goal to measure the abundances of 29 elements. Such a large number of high-resolution spectra necessitate the development of a reduction pipeline optimized for speed, accuracy, and consistency. We outline the design and structure of the IRAF-based reduction pipeline that we developed, specifically for GALAH, to produce fully calibrated spectra aimed for subsequent stellar atmospheric parameter estimation. The pipeline takes advantage of existing IRAF routines and other readily available software so as to be simple to maintain, testable, and reliable. A radial velocity and stellar atmospheric parameter estimator code is also presented, which is used for further data analysis and yields a useful verification of the reduction quality. We have used this estimator to quantify the data quality of GALAH for fibre cross-talk level (≲0.5 per cent) and scattered light (~5 counts in a typical 20 min exposure), resolution across the field, sky spectrum properties, wavelength solution reliability (better than 1 kms-1 accuracy), and radial velocity precision. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00358711
Volume :
464
Issue :
3
Database :
Academic Search Index
Journal :
Monthly Notices of the Royal Astronomical Society
Publication Type :
Academic Journal
Accession number :
120223986
Full Text :
https://doi.org/10.1093/mnras/stw2064