Abstract
Ultra-faint dwarf galaxies represent the extreme end of the distribution of galaxy properties: the least luminous, least chemically enriched, and most dark-matter-dominated galaxies known. Hence, they are important targets for understanding dark matter and galaxy formation. The race is on to learn all we can about the Milky Way’s newly discovered small neighbors. However, there are several observational challenges in understanding such faint systems. The presence or absence of dark matter, and thus whether they are indeed galaxies, remains unclear in some of the recently discovered systems. The existing dynamical analyses rely heavily on the assumptions of dynamical equilibrium. Yet, there are observational clues that many are experiencing significant tidal stripping as they orbit the Milky Way. In this talk, I will present the key results from our in-depth investigation into their elusive nature, using Magellan/Megacam, HST, MMT/Hectochelle, and Gaia-DR2. In particular, our recent work is the first comprehensive study of the tidal signatures in ultra-faint dwarf galaxies. Additionally, I will share our ambitious surveys to study the faintest dwarfs beyond the Local Group. Finally, I will conclude with our ongoing efforts to explore the discovery space in the LSST-era by creating mock observations of representative dwarf galaxies.