Solo Dwarfs I: Survey introduction and first results for the Sagittarius
  Dwarf Irregular Galaxy
  We introduce the Solitary Local Dwarfs Survey (Solo), a wide field
photometric study targeting every isolated dwarf galaxy within 3 Mpc of the
Milky Way. Solo is based on (u)gi multi-band imaging from CFHT/MegaCam for
northern targets, and Magellan/Megacam for southern targets. All galaxies
fainter than Mv = -18 situated beyond the nominal virial radius of the Milky
Way and M31 (>300 kpc) are included in this volume-limited sample, for a total
of 42 targets. In addition to reviewing the survey goals and strategy, we
present results for the Sagittarius Dwarf Irregular Galaxy (Sag DIG), one of
the most isolated, low mass galaxies, located at the edge of the Local Group.
We analyze its resolved stellar populations and their spatial distributions. We
provide updated estimates of its central surface brightness and integrated
luminosity, and trace its surface brightness profile to a level fainter than 30
mag./sq.arcsec. Sag DIG is well described by a highly elliptical (disk-like)
system following a single component Sersic model. However, a low-level
distortion is present at the outer edges of the galaxy that, were Sag DIG not
so isolated, would likely be attributed to some kind of previous tidal
interaction. Further, we find evidence of an extremely low level, extended
distribution of stars beyond 5 arcmins (>1.5 kpc) that suggests Sag DIG may be
embedded in a very low density stellar halo. We compare the stellar and HI
structures of Sag DIG, and discuss results for this galaxy in relation to other
isolated, dwarf irregular galaxies in the Local Group.
