The selection function of the LAMOST Spectroscopic Survey of the Galactic Anticentre

TL;DR

This paper thoroughly analyzes the selection function of the LAMOST Spectroscopic Survey of the Galactic Anti-centre, providing correction methods to enable accurate scientific investigations of the Milky Way's structure.

Contribution

It offers a detailed evaluation of the LSS-GAC survey's selection function and provides correction tools for its value-added catalogues, enhancing their scientific utility.

Findings

Selection function can be evaluated in detail for LSS-GAC.

Selection function corrections are provided for all reliable spectroscopic measurements.

The corrections enable unbiased studies of the Milky Way's chemodynamical structure.

Abstract

We present a detailed analysis of the selection function of the LAMOST Spectroscopic Survey of the Galactic Anti-centre (LSS-GAC). LSS-GAC was designed to obtain low resolution optical spectra for a sample of more than 3 million stars in the Galactic anti-centre. The second release of value-added catalogues of the LSS-GAC (LSS-GAC DR2) contains stellar parameters, including radial velocity, atmospheric parameters, elemental abundances and absolute magnitudes deduced from 1.8 million spectra of 1.4 million unique stars targeted by the LSS-GAC between 2011 and 2014. For many studies using this database, such as those investigating the chemodynamical structure of the Milky Way, a detailed understanding of the selection function of the survey is indispensable. In this paper, we describe how the selection function of the LSS-GAC can be evaluated to sufficient detail and provide selection function corrections for all spectroscopic measurements with reliable parameters released in LSS-GAC DR2. The results, to be released as new entries in the LSS-GAC value-added catalogues, can be used to correct the selection effects of the catalogue for scientific studies of various purposes.