The Stellar Density Profile of the Distant Galactic Halo
  We use extensive gravity-sensitive DDO 51 photometry over 5100 square
degrees, combined with SDSS broadband photometry, to select a catalog of $\sim
4,000$ giant stars covering a large fraction of the high Galactic latitude sky
and reaching out to $\sim 80$ kpc in the Galactic halo. This sample of bright
and unbiased tracers enables us to measure the radial profile and 3D structure
of the stellar halo to large distance which had previously only been measured
with sparse tracers or small samples. Using population synthesis models to
reproduce the observed giant star luminosity function, we find that the halo
maintains a $r^{-3.5}$ profile from $30$ to $80$ kpc with no signs of a
truncation or sharp break over this range. The radial profile measurement is
largely insensitive to individual halo substructure components, but we find
that attempting to measure the shape of the halo is overwhelmed by the
Sagittarius stream such that no ellipsoidal shape is a satisfactory description
in this region. These measurements allow us to begin placing the Milky Way in
context with the growing sample of external galaxies where similar halo profile
measurements are available, with the goal of further linking the properties of
stellar halos to the accretion histories that formed them.
