Disk or Halo white dwarfs? Kinematic analysis of high proper motion surveys

TL;DR

This paper introduces a new kinematic analysis method for high proper motion surveys, applied to white dwarf data, resulting in a lower local space density estimate that challenges previous claims about their contribution to dark matter.

Contribution

It presents an alternative kinematic analysis technique and provides revised estimates of halo white dwarf density, questioning their role in dark matter composition.

Findings

Estimated local WD density is (1-2) x 10^{-5} MSun/pc^{3}

Result is an order of magnitude lower than previous studies

White dwarfs contribute only 0.1%-0.2% to local dark matter

Abstract

We present an alternative method for the kinematic analysis of high proper motion surveys and discuss its application to the survey of Oppenheimer et al. (2001) for the selection of reliable halo white dwarfs (WDs). The local WD space density we estimate is (1-2) 10^{-5}MSun/pc^{3}, which is about an order of magnitude smaller than the value derived in Oppenheimer et al. (2001), and is consistent with the values obtained from recent reanalyses of the same data (e.g. Reid et al. 2001, Reyle et al. 2001, Torres et al. 2002, Salim et al. 2004). Our result, which corresponds to a fraction of 0.1%-0.2% of the local dark matter, does not support the scenario suggested by the microlensing experiments that ancient cool WDs could contribute significantly to the dark halo of the Milky Way.