Making Hay with ALFALFA

John Salzer

Indiana University

The recently completed ALFALFA blind HI survey has produced an unprecedented catalogue of 21-cm detected objects in the local universe out to z = 0.06. With a sensitivity more than an order of magnitude better than previous wide-field blind HI surveys, ALFALFA represents the current state-of-the-art in neutral hydrogen searches. In this talk I will give a brief overview of the ALFALFA survey, then will describe two optical follow-up projects led by our group at Indiana. The first is a large narrow-band H-alpha imaging study of a volume-limited sample of ALFALFA sources. The second is a deep imaging study of nearby HI clouds that have the characteristics of being low-mass dark matter halos. One of the objects uncovered in this latter study is a nearby dwarf galaxy with fairly unique properties that we dubbed Leo P.