Thesis Defense: Seven Dwarfs and Snow White: a tale of cosmological co-evolution of low-mass galaxies and their host

May 31, 2024 - 1:30 pm to 2:30 pm

Campus, PAB 232

Richie Wang (KIPAC) In Person and zoom

Ph.D. Candidate:  Richie Wang
Research Advisor:  Risa Wechsler

Zoom Link:

Zoom Password: Email for password.

Low-mass galaxies provide rich constraints on galaxy formation, reionization, and the nature of dark matter. However, flexible models of their star formation histories in a cosmological context are lacking. In this talk, I introduce a novel framework for connecting dark matter assembly and galaxy star formation histories based on the empirical model UniverseMachine (UM). My framework is flexible, such that it can be simultaneously constrained by observations over a wide range of galaxy masses, environments, and redshifts, ideal for modeling the large dynamic range spanned by low-mass galaxies and their hosts. The model is constrained using observations of satellite galaxies around 101 Milky Way analogs, from the Satellite Around Galactic Analogs (SAGA) survey, and field galaxies from SDSS. We find that a strong correlation between halo stripping and satellite quenching is required to reconcile the large difference between satellite and field galaxy quenched fractions at low stellar masses. This framework also enables us to jointly model bright dwarf galaxies with ultra-faint dwarfs in the Local Group (Milky Way and M31) anchored on dark matter simulations with embedded disk potentials for baryonic disruption, providing a link between the high redshift and very local universe. I will discuss how the disk-enhanced mass loss is strongly affected by the disk-to-halo mass ratio, and what this implies for interpreting satellites of the Milky Way in a cosmological context. Finally, I will discuss how I extracted more sensitive galaxy clustering information using k-nearest neighbors from an observed galaxy cluster catalog that will help us better understand galaxy-halo connection.