Chris Carr

Date: Tue. November 4th, 2025, 11:30 am-12:30 am
Location: Foldy Room, Rockefeller 221
Add to Google Calendar

Coupling and Collisions of Galaxies and their Atmospheres

The circumgalactic medium (CGM) is a vast, multiphase atmosphere of gas bound to galaxy halos, situated at the intersection of inflows from the cosmic web, swarming satellites, and outflows from central galaxies. Precisely how these diverse processes interact to shape the thermal and kinematic properties of the CGM—and, in turn, how the CGM regulates galaxy evolution—remains a central open question in our understanding of galaxy formation. In this talk, I will first present our simplified, one-dimensional analytic regulator model of the CGM–galaxy connection, which predicts the mass, metal, and energy flows between galaxies and their CGM to explore how low-mass galaxies regulate their star formation. Galaxies, and by extension their halos, are also influenced by their environment of nearby neighbors. I will then present results from idealized hydrodynamical simulations modeling the interaction between a Milky Way–like CGM and an infalling Large Magellanic Cloud-like satellite. We find that the infall of such massive satellites, which may themselves host circumgalactic gas, drives large-scale disruptions in the physical and kinematic structure of the host’s CGM through a combination of gravitational and hydrodynamical effects.