Astronomy Colloquium / Spring 2007

April 4th

Prof. John Salzer

Wesleyan University

Making Hay with ALFALFA - Properties of Galaxies Discovered in "Blind" HI Surveys

I will describe results from recent and current observational programs to systematically study the properties of galaxies detected in surveys that select objects via their 21-cm neutral hydrogen (HI) line emission. Because these HI-selected surveys find galaxies independently of their optical appearance, they are "unbiased" in the sense that they include large numbers of dwarf and low-surface-brightness galaxies that are historically under-represented in traditional optical galaxy catalogs. Here we report results from broad-band and narrow-band H-Alpha imaging projects, as well as present nebular spectroscopy of HII regions taken with the goal of measuring chemical abundances.