Characterizing the Gaia radial velocity sample selection function in its native photometry. Issue 1 (20th October 2020)

• Record Type: Journal Article
• Authors: Rybizki, Jan; Rix, Hans-Walter; Demleitner, Markus; Bailer-Jones, Coryn A L; Cooper, William J
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 500:Issue 1(2021)
• Page Start: 397
• Page End: 409
• Publication Date: 2020-10-20
• Subjects: space vehicles: instruments -- virtual observatory tools -- software: public release -- Galaxy: kinematics and dynamics -- Galaxy: stellar content; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3089
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: The Gaia Data Release 2 (DR2) radial velocity sample (GDR2RVS ), which provides six-dimensional phase-space information on 7.2 million stars, is of great value for inferring properties of the Milky Way. Yet a quantitative and accurate modelling of this sample is hindered without knowledge and inclusion of a well-characterized selection function. Here we derive the selection function through estimates of the internal completeness, i.e. the ratio of GDR2RVS sources compared to all Gaia DR2 sources (GDR2all ). We show that this selection function or 'completeness' depends on basic observables, in particular the apparent magnitude G RVS and colour G − G RP, but also on the surrounding source density and on sky position, where the completeness exhibits distinct small-scale structure. We identify a region of magnitude and colour that has high completeness, providing an approximate but simple way of implementing the selection function. For a more rigorous and detailed description we provide python code to query our selection function, as well as tools and adql queries that produce custom selection functions with additional quality cuts.