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

B.Goldman, C.Afonso et al.
(the EROS collaboration)

Abstract:

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 pc³ 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 (99).

Keywords:

Galaxy: halo – Galaxy: kinematics and dynamics – dark matter – white dwarfs

Comments:

5 pages, 2 postscript figures

Status:

To be published by A&A

 

Postscript (288 kb) Gzipped postscript (116 kb) PDF (697 kb)