A Catalog of 531 White Dwarf Candidates in the Local Galactic Halo from Gaia Data Release 2. (arXiv:2007.05153v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kim_B/0/1/0/all/0/1">Bokyoung Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lepine_S/0/1/0/all/0/1">Sebastien Lépine</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Medan_I/0/1/0/all/0/1">Ilija Medan</a>
We present a catalog of 531 white dwarf candidates that have large apparent
transverse motions relative to the Sun ($v_{T} > 200$ km s$^{-1}$), thus making
them likely members of the local Galactic halo population. The candidates were
selected from the Gaia Data Release 2, and are located in a great circle with
$20^circ$ width running across both Galactic poles and Galactic center and
anti-center, a zone that spans 17.3% of the sky. The selection used a
combination of kinematic and photometric properties, derived primarily from
Gaia proper motions, $G$ magnitudes, and $G_{{rm BP}},-,G_{{rm RP}}$ color,
and including parallax whenever available. Additional validation of the white
dwarf candidates is made using PanSTARRS photometric ($gri$) data. Our final
catalog includes not only stars having full kinematic and luminosity estimates
from reliable Gaia parallax, but also stars with presently unreliable or no
available Gaia parallax measurements. We argue that our method to select local
halo objects with and without reliable parallax data leads us to rounding up
all possible halo white dwarfs in the Gaia catalog (in that particular section
of that sky) with recorded proper motions $> 40$ mas yr$^{-1}$, and that pass
our $v_{T} > 200$ km s$^{-1}$ threshold requirement. We expect this catalog
will be useful for the study of the white dwarf population of the local
Galactic halo.
We present a catalog of 531 white dwarf candidates that have large apparent
transverse motions relative to the Sun ($v_{T} > 200$ km s$^{-1}$), thus making
them likely members of the local Galactic halo population. The candidates were
selected from the Gaia Data Release 2, and are located in a great circle with
$20^circ$ width running across both Galactic poles and Galactic center and
anti-center, a zone that spans 17.3% of the sky. The selection used a
combination of kinematic and photometric properties, derived primarily from
Gaia proper motions, $G$ magnitudes, and $G_{{rm BP}},-,G_{{rm RP}}$ color,
and including parallax whenever available. Additional validation of the white
dwarf candidates is made using PanSTARRS photometric ($gri$) data. Our final
catalog includes not only stars having full kinematic and luminosity estimates
from reliable Gaia parallax, but also stars with presently unreliable or no
available Gaia parallax measurements. We argue that our method to select local
halo objects with and without reliable parallax data leads us to rounding up
all possible halo white dwarfs in the Gaia catalog (in that particular section
of that sky) with recorded proper motions $> 40$ mas yr$^{-1}$, and that pass
our $v_{T} > 200$ km s$^{-1}$ threshold requirement. We expect this catalog
will be useful for the study of the white dwarf population of the local
Galactic halo.
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