The GALAH Survey: Data Reduction and Management

We present data reduction procedures used in the GALAH survey, utilizing the multi-fibre spectroscope HERMES and the 3.9 meter Anglo-Australian telescope. GALAH is a unique survey, targeting 1 million stars brighter than magnitude V=14 with a resolution of 28,000 and a goal to measure abundances of 30 elements. We outline the design and present all the steps in the Iraf-based reduction pipeline. The pipeline takes advantage of existing Iraf routines and other readily available software in order to be simple to maintain, tested and reliable. A radial velocity and stellar atmospheric parameter estimator software is also presented, as it is the last step in the reduction pipeline, before the data is released to collaborators. Together with the description of the pipeline we also provide quality analysis of the GALAH spectra; level of fibre cross talk and scattered light, resolution across the field, sky spectrum properties, wavelength solution reliability and the radial velocity accuracy.

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