Random Forest identification of the thin disk, thick disk and halo Gaia-DR2 white dwarf population

Abstract

Gaia-DR2 has provided an unprecedented number of white dwarf candidates of our Galaxy. In particular, it is estimated that Gaia-DR2 has observed nearly 400,000 of these objects and close to 18,000 up to 100 pc from the Sun. This large quantity of data requires a thorough analysis in order to uncover their main Galactic population properties, in particular the thin and thick disk and halo components. Taking advantage of recent developments in artificial intelligence techniques, we make use of a detailed Random Forest algorithm to analyse an 8-dimensional space (equatorial coordinates, parallax, proper motion components and photometric magnitudes) of accurate data provided by Gaia-DR2 within 100 pc from the Sun. With the aid of a thorough and robust population synthesis code we simulated the different components of the Galactic white dwarf population to optimize the information extracted from the algorithm for disentangling the different population components. The algorithm is first tested in a known simulated sample achieving an accuracy of 85.3%. Our methodology is thoroughly compared to standard methods based on kinematic criteria demonstrating that our algorithm substantially improves previous approaches. Once trained, the algorithm is then applied to the Gaia-DR2 100 pc white dwarf sample, identifying 12,227 thin disk, 1,410 thick disk and 95 halo white dwarf candidates, which represent a proportion of 74:25:1, respectively. Hence, the numerical spatial densities are $(3.6\pm 0.4)\times 10^{-3}\mathrm{p}{\mathrm{c}}^{-3}$, $(1.2\pm 0.4)\times 10^{-3}\mathrm{p}{\mathrm{c}}^{-3}$ and $(4.8\pm 0.4)\times 10^{-5}\mathrm{p}{\mathrm{c}}^{-3}$ for the thin disk, thick disk and halo components, respectively. The populations thus obtained represent the most complete and volume-limited samples to date of the different components of the Galactic white dwarf population.

18 pages, 11 figures and 3 tables. Accepted for publication in MNRAS

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Cited by in corpus (10)

• A catalogue of white dwarfs in Gaia EDR3
• $Gaia$ white dwarfs within 40 pc II: the volume-limited northern hemisphere sample
• The Canada-France Imaging Survey: Reconstructing the Milky Way Star Formation History from its White Dwarf Population
• White dwarf-main sequence binaries from Gaia EDR3: the unresolved 100pc volume-limited sample
• Unsupervised star, galaxy, qso classification: Application of HDBSCAN
• Lithium pollution of a white dwarf records the accretion of an extrasolar planetesimal
• The Gaia DR2 halo white dwarf population: the luminosity function, mass distribution and its star formation history
• A population synthesis fitting of the $Gaia$ resolved white dwarf binary population within 100 pc
• Gaia0007-1605: an old triple system with an inner brown dwarf-white dwarf binary and an outer white dwarf companion
• The effects of unresolved double-degenerates in the white dwarf luminosity function