Galactic and Stellar Evolution with Medium-Resolution Spectroscopy
Evan Kirby



A complete description of a galaxy can hardly be deduced from a single star, and the entirety of stellar evolution can hardly be inferred from a single snapshot in time. Rather, holistic pictures of galactic and stellar evolution are made possible by large samples of stars. I will describe three ways in which the Keck/DEIMOS multi-object, medium-resolution spectrograph has aided the understanding of galactic and chemical evolution--as well as uncovered some major puzzles: (1) Gas outflows shape the stellar populations of galaxies, and small galaxies are particularly susceptible to outflows. In fact, DEIMOS has revealed that dwarf galaxies lose a shocking amount of metals. (2) The remote dwarf galaxy VV124 looks in all respects like other Local Group dwarfs, but how did it end up so spheroidal and gas-poor despite its extreme isolation, 1.3 Mpc away from the nearest large galaxy? (3) Evolved red giants have no right to have any lithium. Nonetheless, I have found 13 such objects in dwarf galaxies. They are not unusual in any measurable regard except for their lithium content, which may indicate that the Li-rich phenomenon is not necessarily rare--just brief.