Special Theoretical Physics Seminar - Lina Necib, Caltech - “Dark Matter in the Era of Gaia”

“Dark Matter in the Era of Gaia”
The Gaia mission has provided distance and velocity measurements of over a billion stars in the Milky Way, making it the largest stellar catalog at hand. Simultaneously, recent developments in cosmological simulations have made it possible to track stars and dark matter in realistic Milky Way-like galaxies. In this talk, I will demonstrate how using cutting-edge simulations and Gaia data in tandem has enabled me to start building the first local map of the cold dark matter phase space distribution in our Galaxy. Doing so led me to discover Nyx, a stream of stars in the solar neighborhood that I identified using machine learning methods. Nyx, potentially the result of a prograde merger, is crucial in understanding the formation of the disk of the Milky Way as it might have been associated with an accreted dark disk. I will then show that obtaining such an empirical velocity distribution will have extensive ramifications for dark matter searches. Finally, I will summarize my future strategies to fully map out the phase space distribution of dark matter in the Milky Way, and how they will be used as probes of the particle nature of dark matter.
Host: Nikhil Padmanabhan