The Most Distant Stars in the Milky Way
  We report on the discovery of the most distant Milky Way (MW) stars known to
date: ULAS J001535.72$+$015549.6 and ULAS J074417.48$+$253233.0. These stars
were selected as M giant candidates based on their infrared and optical colors
and lack of proper motions. We spectroscopically confirmed them as outer halo
giants using the MMT/Red Channel spectrograph. Both stars have large estimated
distances, with ULAS J001535.72$+$015549.6 at $274 \pm 74$ kpc and ULAS
J074417.48$+$253233.0 at 238 $\pm$ 64 kpc, making them the first MW stars
discovered beyond 200 kpc. ULAS J001535.72$+$015549.6 and ULAS
J074417.48$+$253233.0 are both moving away from the Galactic center at $52 \pm
10$ km s$^{-1}$ and $24 \pm 10$ km s$^{-1}$, respectively. Using their
distances and kinematics, we considered possible origins such as: tidal
stripping from a dwarf galaxy, ejection from the MW's disk, or membership in an
undetected dwarf galaxy. These M giants, along with two inner halo giants that
were also confirmed during this campaign, are the first to map largely
unexplored regions of our Galaxy's outer halo.
