Dartmouth Events

Abstract: Understanding the behavior of dark matter remains a top priority as it constitutes 85% of all matter in the Universe. Its existence is essential for explaining the formation and structure of galaxies, and, therefore, for understanding the evolution of the Universe. Although dark matter is invisible to current detection methods, there are opportunities to study its nature by observing its interactions with observable matter. In this thesis, I explore the currently favored dark matter model, ΛCDM, through two different avenues: stellar streams and dwarf galaxies. Stellar streams are disrupted dwarf galaxies or globular clusters orbiting the Milky Way. They provide an excellent probe of dark matter subhalo behavior as irregularities in their otherwise cohesive structure reveal a record of previous subhalo impacts. I extract, analyze, and model the Ylgr stellar stream. I find that for Ylgr, its unique structure cannot be explained by the unperturbed model, opening the possibility for a subhalo impact history. I explore future work involving modeling Ylgr with subhalo impact. Secondly, I explore satellite galaxy candidates discovered from the survey Identifying Dwarfs of MC Analog GalaxiEs (ID-MAGE), which focuses on dwarf galaxy hosts in a range of environments. The number and properties of satellites serve as important tests of the ΛCDM model, particularly because ΛCDM remains relatively untested at these small scales. I reduce the spectra of these candidates. For those containing HI lines, I provide their widths. I discuss the future work following up these satellite candidates and the implication of the survey. Both methods help to constrain the nature of dark matter under ΛCDM.

Advisor: Professor Burcin Mutlu-Pakdil

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Meeting ID: 943 8100 6459
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