Physics Colloquium
Extragalactic Archaeology
Dr. Evan N. Kirby
Assistant Professor of Astronomy
California Institute of Technology
Galactic archaeology is the use of the velocities and abundances of stars to learn about the history of the Milky Way's formation and nucleosynthesis. I will present my work on extra-galactic archaeology, targeting external galaxies. First, I will discuss stellar metallicities in nearby galaxies. Even though galaxies at all masses have a diversity of chemical evolution histories, all galaxies obey a tight mass-metallicity relation, reflective of the power of stellar feedback. Second, I will show that abundance ratios, like [alpha/Fe], reveal the personalities of dwarf galaxies. Specifically, the dwarf spheroidal satellites of the Milky Way show more rapid, truncated evolution compared to the leisurely chemical evolution of isolated dwarf irregular galaxies. Third, I will connect these concepts to present a unified view of the past, present, and future of the Andromeda galaxy, its satellite galaxies, its stellar streams, and its halo.
All interested persons are invited to attend remotely—email physics@nd.edu for information.