August 11-15, 2014


White Dwarfs in SDSS DR10.

Nicola Pietro Gentile Fusillo (University of Warwick)

Boris Gänsicke (University of Warwick)

Currently the largest catalogue of spectroscopically identified WDs is based on the 7th data release (DR) of the Sloan Digital Sky Survey and contains over 20000 WDs (Kleiman et al. 2013). However, only a fraction of all WDs in the photometric footprint of SDSS have been spectroscopically followed up.

Using DR7 spectroscopy as a training sample, we developed a method to select high confidence photometric WD candidates. The novelty of our selection is that it allows us to assign to any object with multi-colour and proper motion data a well-defined "probability of being a white dwarf" (or a contaminant). Follow-up spectroscopy of 19 WD candidates spanning a range of such probabilities corroborated the reliability of the method. Exploiting this selection method we compiled a catalogue (Gentile Fusillo et al. in prep) which currently covers the entire photometric footprint of SDSS, 14555sq deg, with a limiting magnitude of g ≤19. However we plan to extend the sky coverage as additional deep multi-colour large area surveys become available.

DR10 includes over 1.4 million spectra taken with the new BOSS spectrograph, which improves over the original SDSS spectograph in both resolution and wavelength coverage, but has so far not been systematically mined for WD science. As part of this project, we also inspected over 8000 BOSS spectra of bright ( g ≤19) colour selected sources and classified 1765 new WDs.
We will discuss a number of highlights from our DR10 WD sample, focusing on the 270 metal-polluted WDs identified so far and in particular on the follow up of a few new DZs which show strong pollution from elements other than Ca and IR excess emission consistent with the presence of debris discs.

Mode of presentation: oral