Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
Speaker: Keith Bechtol, UW Madison Physics Department
Abstract: The stellar halo of the Milky Way represents only ~1% of the total stellar mass of our Galaxy, but is rich with clues regarding the formation history of the Milky Way, the properties of the first stars and galaxies, and the local distribution of dark matter. The current generation of wide-field optical/NIR imaging surveys including SDSS, DES, Pan-STARRS, Gaia, and HSC-SSP has allowed us to catalog more than a billion individually resolved stars out to the Milky Way viral radius and beyond with precise multiband photometry, proper motions, and light curves for variable stars. These datasets, in combination with follow-up spectroscopy, provide new perspectives on the dynamical and chemical history of the Milky Way and its satellites, and ever more stringent constraints on the fundamental nature of dark matter. I will discuss these topics, with a focus on recent results from the Dark Energy Survey (DES), a 5000 square degree imaging survey of the south Galactic cap to ~24th magnitude in the grizY bands.