EROS 2 proper motion survey: Constraints on the halo white dwarfs

. We are conducting a 377 ◦ 2 proper motion survey in the ∼ V and I bands in order to determine the cool white dwarf contribution to the Galactic dark matter. Using the 250 ◦ 2 for which we possess three epochs, and applying selection criteria designed to isolate halo-type objects, we find no candidates in a 5500 pc 3 effective volume for old, fast M V = 17 white dwarfs. We check the detection efficiency by cross-matching our catalogue with Luyten’s NLTT catalogue. The halo white dwarf contribution cannot exceed 5% (95% C.L.) for objects with M V = 17 and 1 ≤ V − I ≤ 1 . 5. The same conclusion applies to a 14 Gyr halo composed of white dwarfs with hydrogen atmosphere, as modeled by Chabrier.