Simulating Gaia performances on white dwarfs

One of the most promising space missions of the European Space Agency is the astrometric satellite Gaia , which will provide very precise astrometry and multicolour photometry, for all 1.3 billion objects to   V ∼ 20  , and radial velocities with accuracies of a few km s⁻¹ for most stars brighter than   V ∼ 17  . Consequently, full homogeneous six-dimensional phase-space information for a huge number of stars will become available. Our Monte Carlo simulator has been used to estimate the number of white dwarfs potentially observable by Gaia . From this we assess the white dwarf luminosity functions that Gaia will obtain and discuss in depth the scientific returns of Gaia in the specific field of white dwarf populations. Scientifically attainable goals include, among others, a reliable determination of the age of the Galactic disc, a better knowledge of the halo of the Milky Way and the reconstruction of the star formation history of the Galactic disc. Our results also demonstrate the potential impact of a mission such as Gaia within the context of current understanding of white dwarf cooling theory.