Stars in the Local Galactic Thick Disk and Halo in Gaia EDR3: A catalogue of Half a Million Local Main-sequence Stars with Photometric Metallicities

Bokyoung Kim, Sebastien Lépine

Research output: Contribution to journalArticlepeer-review

Abstract

We present a catalogue of 551, 214 main-sequence stars in the local (𝑑 < 2 kpc) Galactic thick disk and halo, based on a search of stars with large proper motions (𝜇tot > 40.0 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.
Original languageEnglish
Pages (from-to)4308-4329
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Volume510
Issue number3
Early online date22 Dec 2021
DOIs
Publication statusPublished - 1 Mar 2022

Keywords

  • astro-ph.GA
  • astro-ph.SR

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