The halo white dwarf population

Halo white dwarfs can provide important information about the properties an d evolution of the Galactic halo. In this paper we compute, assuming a stan dard initial mass function (IMF) and updated models of white dwarf cooling, the expected luminosity function, both in luminosity and in visual magnitu de, for different star formation rates. We show that a deep enough survey ( limiting magnitude greater than or similar to 20) could provide important i nformation about the halo age and the duration of the formation stage. We a lso show that the number of white dwarfs produced using the recently propos ed biased IMFs cannot represent a large fraction of the halo dark matter if they are constrained by the presently observed luminosity function. Furthe rmore, we show that a robust determination of the bright portion of the lum inosity function can provide strong constraints on the allowable IMF shapes .