Stars in the local galactic thick disc and halo in Gaia EDR3: a catalogue of half a million local main-sequence stars with photometric metallicities
Abstract
We present a catalogue of 551 214 main-sequence stars in the local (d < 2 kpc) Galactic thick disc and halo, based on a search of stars with large proper motions ($\mu _{\rm tot} \gt 40.0~\rm mas\, yr^{-1}$) in the Gaia Early Data Release 3. We derive photometric metallicity calibrated from the colour-luminosity-metallicity distribution of 20 047 stars with spectroscopic metallicities, collected from various spectroscopic surveys, including SDSS SEGUE/APOGEE, GALAH DR3, and LAMOST DR6. We combine these results to construct an empirical colour-magnitude-metallicity grid, which can be used to estimate photometric metallicities for low-mass metal-poor stars of K and M subtypes from their absolute G magnitude and colour values. We find that low-mass, high-velocity stars in our catalogue share similar kinematics as reported in recent studies of more luminous Galactic halo stars. The pseudo-kinematic analysis of our sample recovers the main local halo structures, including the Gaia-Enceladus Stream and the Helmi stream; aside from these, the local halo stars appear to show a remarkably smooth distribution in velocity space. Since the future Gaia data release will provide radial velocity measurements for only a small number of our sample, our catalogue provides targets of high interest for the future spectroscopic observation programs.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2022
- DOI:
- 10.1093/mnras/stab3671
- arXiv:
- arXiv:2112.07419
- Bibcode:
- 2022MNRAS.510.4308K
- Keywords:
-
- catalogues;
- stars: abundances;
- stars: kinematics and dynamics;
- Galaxy: halo;
- Galaxy: solar neighbourhood;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted by MNRAS. 23 pages, 19 figures, 6 tables. Please contact authors to access the main table (Table 6). The authors plan to upload Table 6 in machine-readable format to VizieR soon