The Gaia white dwarf population within 100 pc of the Sun

Torres, S.
Rebassa-Mansergas, A.
Jiménez-Esteban, F.M.
Cantero, C.
Canals, P.
Skorobogatov, G.
Solano, E.
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The recent Gaia Data Release 2 has provided an unprecedented sample of the local white dwarf population. The high astrometric resolution and the photometry provided by Gaia allows to build a clean magnitude-color diagram that, with the aid of the most updated population synthesis simulator, permit us to select the sample of white dwarf candidates. Our analysis shows that Gaia has virtually identified all white dwarfs within 100 pc from the Sun. Additionally, we use the Virtual Observatory tool VOSA to derive effective temperatures and luminosities for our sources by fitting their spectral energy distributions. The Gaia 100 pc white dwarf population is clearly dominated by cool (~8,000 K) objects and reveals a significant population of massive (M ~ 0:8M ) white dwarfs, of which no more than ~30 - 40% can be attributed to hydrogen-deficient atmospheres. Preliminary results including white dwarf mergers seem not to explain this excess unless some ad hoc hypothesis are adopted. Finally, we use an Intelligent Artificial algorithm based on the Random Forest method to disentangle the different Galactic components of the white dwarf population. Our results show that the thin, thick and halo ratio in the 100 pc sample is 89:11:1, identifying 97 halo white dwarf candidates.

The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018