The Faintest Galaxies and their Dark Matter Halos

Jul 23, 2020 - 11:00 am to 12:00 pm
Ethan Nadler (KIPAC) via zoom

Zoom Recording

As luminous tracers of the smallest dark matter halos, ultra-faint dwarf galaxies offer a unique window into the physics of galaxy formation and dark matter. Our census of these extremely faint systems has drastically improved in recent years as a result of detailed searches in deep photometric datasets, including those from the Dark Energy Survey. In this talk, we describe recent advances in our understanding of these systems, focusing on their implications for 1) the galaxy--halo connection, reionization physics, and high-redshift galaxy formation, and 2) the microphysical properties of dark matter. We show that the lack of a cutoff in the observed abundance of ultra-faint galaxies yields among the strongest astrophysical constraints to date on the warmth, Standard Model couplings, and de Broglie wavelength of dark matter, and we discuss the implications of these constraints for particle models including sterile neutrinos, generalized WIMPs, and ultra-light axions.