Astrophysics Seminar: Dr. Anna Nierenberg, University of California, Merced


Location: zoom

Star formation in low-mass halos, and the nature of dark matter with strong gravitational lensing

Dr. Anna Nierenberg
Assistant Professor
University of California, Merced

The nature of dark matter remains one of the major puzzles of modern physics. Traditional tests of the nature of dark matter rely on observations of stars and galaxies which form within larger dark matter structures known as halos. The abundance of dark matter halos, and thus the abundance of galaxies, depends on the fundamental properties of dark matter such as its free streaming-length and self-interaction cross section. Cold Dark Matter (CDM) predictions match observations of galaxies remarkably well for mass scales above that of the Milky Way. At lower masses such comparisons become more difficult, as galaxies become fainter, and theoretical predictions for how galaxies form become more uncertain. I will present my work which involves two complementary approaches to measuring the abundance of small-scale structure. First I discuss my measurements of the number of low-mass satellite galaxies across more than half the age of the Universe and in a variety of environments, and demonstrate how these measurements provide a deeper understanding of the physics of star formation in low-mass dark matter halos.  I will also present my novel approach to strong gravitational lensing which makes it possible to detect low-mass dark matter halos in a much larger number of systems than was previously possible. I will conclude by discussing future prospects for these programs given the next generation of ground and space based facilities.

All interested persons are invited to attend remotely—email for information.