Mapping the Local Halo: Statistical Parallax Analysis of SDSS Low-Mass
  Subdwarfs
  We present a statistical parallax study of nearly 2,000 M subdwarfs with
photometry and spectroscopy from the Sloan Digital Sky Survey. Statistical
parallax analysis yields the mean absolute magnitudes, mean velocities and
velocity ellipsoids for homogenous samples of stars. We selected homogeneous
groups of subdwarfs based on their photometric colors and spectral appearance.
We examined the color-magnitude relations of low-mass subdwarfs and quantified
their dependence on the newly-refined metallicity parameter, zeta. We also
developed a photometric metallicity parameter, delta(g-r), based on the g-r and
r-z colors of low-mass stars and used it to select stars with similar
metallicities. The kinematics of low-mass subdwarfs as a function of color and
metallicity were also examined and compared to main sequence M dwarfs. We find
that the SDSS subdwarfs share similar kinematics to the inner halo and thick
disk. The color-magnitude relations derived in this analysis will be a powerful
tool for identifying and characterizing low-mass metal-poor subdwarfs in future
surveys such as GAIA and LSST, making them important and plentiful tracers of
the stellar halo.
