RSAA Colloquia / Seminars / Feast-of-Facts: Friday, 12 April 2019, 14:00-15:00; CSO Common Room

Nicolas Martin

"Mining and mapping the first generations of stars with the Pristine CaH&K survey"

I will present the first results of the Pristine survey, a Franco-Canadian photometric survey of the Milky Way halo performed with the new CaHK filter on CFHT’s MegaCam. Currently covering ~5,000 deg^2, this survey leads to an efficient metallicity decomposition of the Milky Way halo. In particular, I will show how efficient Pristine is in selecting the metal-poor end of the metallicity distribution ([Fe/H]<-2.5) to hunt for the very rare extremely metal-poor stars (bearer of the chemical imprint of the first stars). Our spectroscopic follow-up campaign shows Pristine is very efficient at selecting very metal-poor stars from our photometry alone. A dedicated part of the survey also focuses on the enigmatic very faint (and therefore metal-poor) Milky Way dwarf galaxies found over the last decade. I will show that Pristine can isolating likely member stars and that it opens a well-needed window onto the detailed study of these systems that are often used as near-field cosmological probes.