TY - JOUR
T1 - The GALAH survey: the data reduction pipeline
AU - Kos, Janez
AU - Lin, Jane
AU - Zwitter, Tomaž
AU - Žerjal, Maruška
AU - Sharma, Sanjib
AU - Bland-Hawthorn, Joss
AU - Asplund, Martin
AU - Casey, Andrew R.
AU - De Silva, Gayandhi M.
AU - Freeman, Ken C.
AU - Martell, Sarah L.
AU - Simpson, Jeffrey D.
AU - Schlesinger, Katharine J.
AU - Zucker, Daniel
AU - Anguiano, Borja
AU - Bacigalupo, Carlos
AU - Bedding, Timothy R.
AU - Betters, Christopher
AU - Da Costa, Gary
AU - Duong, Ly
AU - Hyde, Elaina
AU - Ireland, Michael
AU - Kafle, Prajwal R.
AU - Leon-Saval, Sergio
AU - Lewis, Geraint F.
AU - Munari, Ulisse
AU - Nataf, David
AU - Stello, Dennis
AU - Tinney, C. G.
AU - Traven, Gregor
AU - Watson, Fred
AU - Wittenmyer, Robert A.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - 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 km s-1
accuracy), and radial velocity precision.
AB - 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 km s-1
accuracy), and radial velocity precision.
KW - atmospheric effects
KW - instrumentation: spectrographs
KW - methods: observational
KW - techniques: spectroscopic
KW - surveys
KW - stars: atmospheres
U2 - 10.1093/mnras/stw2064
DO - 10.1093/mnras/stw2064
M3 - Article
VL - 464
SP - 1259
EP - 1281
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -