Type Ia Supernovae and High Velocity White Dwarfs

I examine the hypothesis that many of the high velocity white dwarfs observed by Oppenheimer et al. (2001) are the remnants of donor stars from binaries that produced type Ia supernovae via the `single degenerate’ channel. If this channel is a significant contributor to the Galactic SN Ia supernova rate, then the local density of such remnants with V>100 km/s could be as high as 2.e-4 per cubic parsec, comparable to the densities found by Oppenheimer et al. This white dwarf population differs from others in that it is composed exclusively of single stars.