We discuss the approach of searching low mass dwarf galaxies , \lesssim 10 ^ { 6 } \textrm { M } _ { \odot } , in the general field , using integrated light surveys .
By exploring the limiting surface brightness-spatial resolution ( \mu _ { \textrm { eff,lim } } - \theta ) parameter space , we suggest that faint field dwarfs in the Local Volume , between 3 and 10 \textrm { Mpc } , are expected to be detected effectively and in large numbers using integrated light photometric surveys , complementary to the classical star counts method .
We use a sample of Local Group dwarf galaxies to construct relations between their photometric and structural parameters , \textrm { M } _ { * } - \mu _ { \textrm { eff,V } } and \textrm { M } _ { * } - \textrm { R } _ { \textrm { eff } } .
We use these relations , along with assumed functional forms for the halo mass function and the stellar mass-halo mass relation , to calculate the lowest detectable stellar masses in the Local Volume and the expected number of galaxies as a function of the limiting surface brightness and spatial resolution .
The number of detected galaxies depends mostly on the limiting surface brightness for distances > 3 \textrm { Mpc } while spatial resolution starts to play a role at distances > 8 \textrm { Mpc } .
Surveys with \mu _ { \textrm { eff,lim } } \sim 30 \textrm { mag arcsec } ^ { -2 } should be able to detect galaxies with stellar masses down to \sim 10 ^ { 4 } \textrm { M } _ { \odot } in the Local Volume .
Depending on the assumed stellar mass-halo mass relation , the expected number of galaxies between 3 and 10 \textrm { Mpc } is 0.04 - 0.35 \textrm { deg } ^ { -2 } , assuming a limiting surface brightness of \sim 29 - 30 \textrm { mag arcsec } ^ { -2 } and a spatial resolution < 4 ^ { \prime \prime } .
We currently look for field dwarf galaxies by performing a blank wide-field survey with the Dragonfly Telephoto Array , optimized for the detection of ultra-low surface brightness structures .