Discovery of diffuse dwarf galaxy candidates around M101
  We have conducted a search of a 9 deg$^{2}$ region of the CFHTLS around the
Milky Way analog M101 (D$\sim$7 Mpc), in order to look for previously unknown
low surface brightness galaxies. This search has uncovered 38 new low surface
brightness dwarf candidates, and confirmed 11 previously reported galaxies, all
with central surface brightness $\mu$(g,0)$>$23mag/arcsec$^{2}$, potentially
extending the satellite luminosity function for the M101 group by $\sim$1.2
magnitudes. The search was conducted using an algorithm that nearly automates
the detection of diffuse dwarf galaxies. The candidates small size and low
surface brightness means that the faintest of these objects would likely be
missed by traditional visual or computer detection techniques. The dwarf galaxy
candidates span a range of $-$7.1 $\geq$ M$_g$ $\geq$ $-$10.2 and half light
radii of 118-540 pc at the distance of M101, and they are well fit by simple
S\'{e}rsic surface brightness profiles. These properties are consistent with
dwarfs in the Local Group, and to match the Local Group luminosity function
$\sim$10-20 of these candidates should be satellites of M101. Association with
a massive host is supported by the lack of detected star formation and the over
density of candidates around M101 compared to the field. The spatial
distribution of the dwarf candidates is highly asymmetric, and concentrated to
the northeast of M101 and therefore distance measurements will be required to
determine if these are genuine members of the M101 group.
