Astrophysics Colloquium: The Hidden Physics of Cosmic Gas: From the Baryon Cycle to Turbulence and Feedback

Abstract: Galaxies evolve within a vast reservoir of diffuse gas that connects them to the cosmic web. This circumgalactic and intergalactic medium plays a central role in the cosmic baryon cycle, regulating the supply of fuel for star formation while receiving energy and chemically enriched material from stellar and black hole feedback. Beyond its role in galaxy evolution, diffuse cosmic gas provides a unique laboratory for investigating fundamental physical processes governing the transport, mixing, and dissipation of matter and energy across a vast range of spatial scales. In this talk, I will present recent results from the Cosmic Ultraviolet Baryon Survey (CUBS), highlighting the multiphase structure, chemical enrichment, and dynamics of diffuse gas across galaxy environments, including low-mass dwarf galaxies where feedback can have particularly profound consequences. I will discuss how observations of gas kinematics and molecular hydrogen shed light on turbulence, energy dissipation, shocks, and cosmic-ray feedback. Finally, I will highlight new opportunities to resolve the gaseous ecosystems of galaxies through gravitational lensing with our latest JWST LACES program and introduce FALCON, a next-generation wide-field spectroscopic facility designed to connect small-scale gas physics with the cosmic baryon cycle.