EROS 2 proper motion survey: Constraints on the halo white dwarfs
  We are conducting a 377-square-degree 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 square degrees 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 14Gyr halo composed of white dwarfs with hydrogen atmosphere, as modeled by Chabrier (99). 
B.Goldman, C.Afonso, Ch.Alard, J.-N.Albert, A.Amadon, J.Andersen,   R.Ansari, E.Aubourg, P.Bareyre, F.Bauer, J.-Ph.Beaulieu,...