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Título:	Random Forest identification of the thin disc, thick disc, and halo Gaia-DR2 white dwarf population
Autor/a:	Torres Gil, Santiago; Cantero, C.; Rebassa Mansergas, Alberto; Skorobogatov, G.; Jiménez Esteban, F. M.; Solano Márquez, Enrique
Otros autores:	Universitat Politècnica de Catalunya. Departament de Física; Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica
Abstract:	Gaia-DR2 has provided an unprecedented number of white dwarf candidates of ourGalaxy. In particular, it is estimated thatGaia-DR2 has observed nearly 400 000 ofthese objects and close to 18 000 up to 100 pc from the Sun. This large quantity ofdata requires a thorough analysis in order to uncover their main Galactic popula-tion properties, in particular the thin and thick disk and halo components. Takingadvantage of recent developments in artificial intelligence techniques, we make useof a detailed Random Forest algorithm to analyse an 8-dimensional space (equato-rial coordinates, parallax, proper motion components and photometric magnitudes)of accurate data provided byGaia-DR2 within 100 pc from the Sun. With the aid ofa thorough and robust population synthesis code we simulated the different compo-nents of the Galactic white dwarf population to optimize the information extractedfrom the algorithm for disentangling the different population components. The algo-rithm is first tested in a known simulated sample achieving an accuracyof 85.3%. Ourmethodology is thoroughly compared to standard methods based on kinematic criteriademonstrating that our algorithm substantially improves previous approaches. Oncetrained, the algorithm is then applied to theGaia-DR2 100 pc white dwarf sample,identifying 12 227 thin disk, 1410 thick disk and 95 halo white dwarf candidates, whichrepresent a proportion of 74:25:1, respectively. Hence, the numerical spatial densitiesare (3.6±0.4)×10-3pc-3, (1.2±0.4)×10-3pc-3and (4.8±0.4)×10-5pc-3forthe thin disk, thick disk and halo components, respectively. The populations thus ob-tained represent the most complete and volume-limited samples to date of the differentcomponents of the Galactic white dwarf population.
Abstract:	Peer Reviewed
Materia(s):	-Àrees temàtiques de la UPC::Física::Astronomia i astrofísica -White dwarf stars -Stars--Luminosity function -Stars--Masses -Stars: white dwarfs -Galaxy: stellar content -Stars: luminosity function -mass function -Estels nans -Galàxies -- Formació
Derechos:	Attribution-NonCommercial-NoDerivs 3.0 Spain http://creativecommons.org/licenses/by-nc-nd/3.0/es/
Tipo de documento:	Artículo - Borrador Artículo
Editor:	Oxford University Press
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