  We present results from an optical search for Local Group dwarf galaxy
candidates associated with the Ultra-Compact High Velocity Clouds (UCHVCs)
discovered by the ALFALFA neutral hydrogen survey. The ALFALFA UCHVCs are
isolated, compact HI clouds with projected sizes, velocities, and estimated HI
masses that suggest they may be nearby dwarf galaxies, but that have no clear
counterpart in existing optical survey data. We observed 26 UCHVCs with the
WIYN 3.5-m telescope and One Degree Imager (ODI) in two broadband filters and
searched the images for resolved stars with properties that match those of
stars in typical dwarf galaxies at distances <2.5 Mpc. We identify one
promising dwarf galaxy candidate at a distance of ~570 kpc associated with the
UCHVC AGC 268071, and five other candidates that may deserve additional
follow-up. We carry out a detailed analysis of ODI imaging of a UCHVC that is
close in both projected distance and radial velocity to the outer-halo Milky
Way globular cluster Pal 3. We also use our improved detection methods to
reanalyze images of five UCHVCs that were found to have possible optical
counterparts during the first phase of the project, and confirm the detection
of a possible stellar counterpart to the UCHVC AGC 249525 at an estimated
distance of ~2 Mpc. We compare the optical and HI properties of the dwarf
galaxy candidates to the results from recent theoretical simulations that model
satellite galaxy populations in group environments, as well as to the observed
properties of galaxies in and around the Local Group.
