On high proper motion white dwarfs from photographic surveys

Abstract

The interpretation of high proper motion white dwarfs detected by Oppenheimer et al (2001) was the start of a lively controversy. While the discoverers identify a large fraction of their findings as dark halo members, others interpret the same sample as essentially made of disc and/or thick disc stars. We use the comprehensive description of Galactic stellar populations provided by the "Besancon" model to produce a realistic simulation of Oppenheimer et al. data, including all observational selections and calibration biases. The conclusion is unambiguous: Thick disc white dwarfs resulting from ordinary hypotheses on the local density and kinematics are sufficient to explain the observed objects, there is no need for halo white dwarfs. This conclusion is robust to reasonable changes in model ingredients. The main cause of the misinterpretation seems to be that the velocity distribution of a proper motion selected star sample is severely biased in favour of high velocities. This has been neglected in previous analyses. Obviously this does not prove that no such objects like halo white dwarfs can exist, but Oppenheimer et al. observations drive their possible contribution in the dark matter halo down to an extremely low fraction.

4 pages, 1 figure, A&A Letters, accepted

References in corpus (10)

• Direct Detection of Galactic Halo Dark Matter
• The Spheroid Luminosity and Mass Functions From HST Star Counts
• A Survey for Cool White Dwarfs and the age of the Galactic Disc
• Cooling sequences and color-magnitude diagrams for cool white dwarfs with hydrogen-atmospheres
• Discovery of high proper motion ancient white dwarfs: nearby massive compact halo objects?
• High-velocity white dwarfs: thick disk, not dark matter
• Early galaxy evolution from deep wide field star counts. II. First estimate of the thick disc mass function
• Is Galactic Dark Matter White ?
• The halo white dwarf population
• A Survey for Faint Stars of Large Proper Motion Using Extra Poss II Plates

Cited by in corpus (21)

• Galactic Searches for Dark Matter
• 3D kinematics of white dwarfs from the SPY project II
• Cool White Dwarfs in the Sloan Digital Sky Survey
• Gaia photometry for white dwarfs
• Monte Carlo simulations of the halo white dwarf population
• Type Ia Supernovae and High Velocity White Dwarfs
• White dwarfs and Galactic dark matter
• A Proper Motion Survey for White Dwarfs with the Wide Field Planetary Camera 2
• Ages of White Dwarf-Red Subdwarf Systems
• EROS 2 proper motion survey: Constraints on the halo white dwarfs
• Absolute Proper Motions to B~22.5: IV. Faint, Low Velocity White Dwarfs and the White Dwarf Population Density Law
• Illuminating the darkness: More evidence from faint-star proper-motions for a cool and warm component to the local dark matter in the Galaxy
• Faint Blue Objects in the Hubble Deep Field South Revealed: White Dwarfs, Subdwarfs, and Quasars
• Disk or Halo white dwarfs? Kinematic analysis of high proper motion surveys
• Simulating a White Dwarf-dominated Galactic Halo
• The contribution of red dwarfs and white dwarfs to the halo dark matter
• Proper Motion Objects in the Hubble Deep Field
• The glow of primordial remnants
• Dark halo baryons not in ancient halo white dwarfs
• The Next Generation Virgo Cluster Survey. XXVIII. Characterization of the Galactic White Dwarf Population
• Luminosity limits on white dwarfs in a Galactic shroud