Abstract

The very beginning of our Universe continues to be largely elusive — even with our advanced observational probes and the most state–of–the–art cosmological simulations, we are left with many unanswered questions including the origins and evolutionary histories of the smallest and most ancient of galaxies —ultra–faint dwarfs. Recent observational advances, such as the third Gaia data release, and cosmological simulations, such as Phat ELVIS, have opened up new opportunities to study the evolutionary histories of our ultra–faint satellite population and use this population as a tool to constrain fundamental Galactic properties. We have been able to place limits on the mechanism responsible for the ultra–faint dwarf galaxies’ quenched star formation, place constraints on the dark matter halo mass of the Milky Way and begin to explore how large scale environments have impacted ultra–faints’ evolutionary histories. Furthering this line of work, I focus on near–field cosmology projects observationally deciphering chemical abundance and star formation history trends that result from our ultra–faints’ previous environments. Using spectroscopic studies of Hydrus I, a satellite of the LMC, and Willman 1, an MW satellite that is not also an LMC satellite, we explore how evolutionary history impacts chemical enrichment, via single or paired elemental trends, such as [Mg/Ti]. These mostly yet–to–be–explored evolutionary histories of Milky Way ultra–faint dwarf satellites help to refine which are true, pristine relics of the first galaxies ever formed and can serve as the most optimal cosmic sites to search for signatures of the first stars ever formed.