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SkyMapper Protected Science Project

Investigating the Galactic White Dwarf Population with SkyMapper

Stephane Vennes (Czech Academy of Sciences), Adela Kawka (CAS), Lilia Ferrario (ANU), Stefan Keller (RSAA), Mike Bessell (RSAA), David Buckley (SAAO), Gary Da Costa (RSAA)

Using SkyMapper multi-band photometry supplemented with ultraviolet and infrared archival data as well as astrometric data products (proper motion) we will extract the first deep-sky catalogue of white dwarfs covering all Galactic latitudes from the Southern Cap to the Galactic plane. In a first step, we will develop the colourimetric criteria based on new model atmospheres that are necessary to discriminate white dwarfs from other populations (e.g., cool subdwarf stars). Next, with SkyMapper team members we will initiate the spectroscopic investigation. The first phase of the programme will exploit existing preliminary data to train our models and selection criteria, and in the second phase we will gradually build a catalogue of white dwarf and other subluminous stars (e.g., EHB) concurrently with the survey build-up. The spectroscopic follow-up will be initiated as soon as practical using world-class facilities such as ESO. The full data set will allow us to constrain white dwarf formation scenarios in the disc and halo of the Galaxy. In addition, a large hidden population of double degenerate stars should emerge from follow-up spectroscopic investigations, which, combined with the WD+MS binary population, will allow us to conduct population synthesis calculations leading to a definitive population census and tight constraints of the white dwarf space distribution and formation rate (luminosity function).