19 low mass hyper-velocity star candidates from the first data release
  of LAMOST survey
  Hyper-velocity stars are believed to be ejected out from the Galactic center
through dynamical interactions between (binary) stars and the central massive
black hole(s). In this paper, we report 19 low mass F/G/K type hyper-velocity
star candidates from over one mil- lion stars of the first data release of the
LAMOST general survey. We determine the unbound probability for each candidate
using a Monte-Carlo simulation by assuming a non-Gaussian proper-motion error
distribution, Gaussian heliocentric distance and radial velocity error dis-
tributions. The simulation results show that all the candidates have unbound
possibilities over 50% as expected, and one of them may even exceed escape
velocity with over 90% probabili- ty. In addition, we compare the metallicities
of our candidates with the metallicity distribution functions of the Galactic
bulge, disk, halo and globular cluster, and conclude that the Galactic bulge or
disk is likely the birth place for our candidates.
