Andromeda XXIX: A New Dwarf Spheroidal Galaxy 200kpc from Andromeda
  We report the discovery of a new dwarf galaxy, Andromeda XXIX, using data
from the recently-released Sloan Digital Sky Survey DR8, and confirmed by
Gemini North telescope Multi-Object Spectrograph imaging data. And XXIX appears
to be a dwarf spheroidal galaxy, separated on the sky by a little more than 15
degrees from M31, with a distance inferred from the tip of the red giant branch
of 730kpc+/-75kpc, corresponding to a three dimensional separation from M31 of
between 205kpc and 227kpc (close to M31's virial radius). Its absolute
magnitude, as determined by comparison to the red giant branch luminosity
function of the Draco dwarf spheroidal, is M_V = -8.3+/-0.4. And XXIX's stellar
populations appear very similar to Draco's; consequently, we estimate a
metallicity for And XXIX of [Fe/H]\sim-1.8. The half-light radius of And XXIX
is 360pc+/-60pc and its ellipticity is 0.35+/-0.06, typical of dwarf satellites
of the Milky Way and M31 at this absolute magnitude range.
