The z = 0 Galaxy Luminosity Function. I. Techniques for Identification of Dwarf Galaxies at ∼10 Mpc

We present a program to study the galaxy luminosity function of the Leo I and Coma I Groups at ∼10 Mpc. We have surveyed over 7 deg2 in Leo I and ∼11 deg2 in Coma I. In this paper, we detail the method we have developed and implemented for identifying on morphological grounds low surface brightness, MR < -10, dwarf galaxies at a distance of 10 Mpc. We also describe extensive Monte Carlo simulations of artificial galaxies, which we use to tune our detection algorithms and evaluate our detection efficiency and parameter recovery as a function of R-band central surface brightness μR(0) and total magnitude RT. We find for a subset of our Leo I data that at the 90% completeness level, we can detect dwarfs comparable to Antlia and Sculptor. Finally, we describe preliminary follow-up observations that confirm we are detecting dwarf spheroidal galaxies in Leo I at 10 Mpc.