White Dwarfs

The white dwarf program in the MWM survey is obtaining multi-epoch BOSS spectra of a large sample of Galactic white dwarfs. These Earth-sized (and consequently intrinsically dim) objects are difficult to identify among the field of much brighter stars. Parallaxes from Gaia have been the key to identifying a homogeneous and nearly-complete all sky sample of white dwarfs for spectroscopic follow-up.

Spectra of white dwarfs
Examples of magnetic WD spectra from SDSS observations (Schmidt et al. 2003)

The white dwarf program draws its sample from the Gaia DR2 catalog of white dwarfs (Gentile Fusillo et al 2019), selecting all targets with a greater than 50% probability of being a white dwarf that are brighter than 20th magnitude in the Gaia DR2 G passband.

Cartons


White Dwarf Cartons in Targeting Generation v0.5.3

In target generation v0.5.3 the following selection function defines the individual carton. The photometry is from Gaia DR2 and the probability of being a white dwarf (PWD) is taken from the catalog of Gentile Fusillo. That catalog can be queried on CasJobs and has been included in the SAS as mos_gaia_dr2_wd.fits.

  • mwm_wd_core
    • G < 20
    • PWD > 0.5

Cadences

All white dwarf targets are observed during dark time and request two epochs of BOSS spectra (dark_2x1).

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