CCA Colloquium: Marla Geha

Date


Title: The Edge of Galaxy Formation: Uniform Kinematics and Metallicities for Milky Way Satellites

Abstract: The Milky Way’s satellite galaxies have been used to constrain dark matter properties and explore the faintest threshold of galaxy formation. These population-level studies rely on properties derived from heterogeneous spectroscopic analyses. Systematic differences between data reduction pipelines and membership criteria can masquerade as astrophysical signals, or obscure real trends. I present the largest self-consistent sample of spectroscopically-derived quantities for Milky Way satellite galaxies and globular clusters based on a homogeneous re-analysis of individual stars observed with the Keck/DEIMOS spectrograph. I demonstrate improved precision in the internal velocity dispersions over literature values, directly translating into improved constraints on their dark matter content and dark matter particle properties. I then explore key relationships including the mass-metallicity and stellar mass-halo mass relationships.

May 1, 2026

Marla Geha: The Edge of Galaxy Formation: Uniform Kinematics and Metallicities for Milky Way Satellites

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