The Chemical Evolution of Dwarf Galaxies
Evan Kirby

The dwarf galaxies in the Local Group are a rich playground for exploring galactic and chemical evolution. I will show that resolved stellar spectroscopy of these galaxies with Keck/DEIMOS has revolutionized our perception of how galaxies process gas and generate metals. In particular, galaxies of all morphological types--contrary to common wisdom--obey a universal stellar mass-metallicity relationship. I will include some of the smallest galaxies, including Segue 2, with a luminosity of only 900 L_sun. I will show that it is the least massive galaxy known, with a stellar velocity dispersion less than 2 km/s. Despite its tiny mass, Segue 2's chemical composition identifies it as a galaxy, not an unusual globular cluster, like NGC 2419.