Particle Physics Seminar: Probing Dark Matter with Galactic Substructure

Abstract:

Observational capabilities of small-scale structures within galaxies has been increasing rapidly in recent years. New and exciting astrophysical data-sets now enable the identification of many such structures within our Milky Way and this data will grow substantially over the next decade. These structures include dwarf satellite galaxies orbiting our Galaxy, cold stream-like objects and other remnants of merger events with the Milky Way. The wealth of new data offers a novel probe of the dark matter components of these objects, allowing one to gain knowledge of the particle nature of the dark matter model itself. In this talk I will discuss a number of avenues with which to utilize the data to study dark matter structure and differentiate between classes of dark matter theories. I will show that satellite galaxies and remnants of merger events with the Milky Way, such as the Sagittarius Stream and dark matter disks from highly disrupted dwarfs, provide valuable information. A particularly interesting finding is that dark matter disks tend to alter the angular momentum of the stellar disk of our Galaxy in a predictable fashion, even for a collisionless cold dark matter model. The resulting tilting motion of the stellar disk will be observable with data from the Gaia Space Telescope and can be used to infer properties of the merger event and its dark matter content. I will highlight a number of results and discuss additional avenues which my group will pursue in upcoming years.

Seminar Organizers: Dr. Michael Geller & Dr. Adi Ashkanzi