Hypervelocity stars in PS1

Reminded by http://arxiv.org/abs/1411.5022
(which is not immediately applicable): we should check
for high-velocity stars towards the bulge....

Possible next steps are as follows:
Devise an LSD quest that finds candidates. Possible selection criteria could be:
-- within 30° off the bulge
-- at a photometric distance consistent with the bulge
-- certain number of epochs with good photometry
A well-measured proper motion that is consistent with three epochs and
implies a velocity above 300 km per second.