APS Colloquium - David Schiminovich/Columbia University

Event Title: Assaying the Atmospheres That Milky Ways Breathe with CHaS+

Speaker Name / Affiliation: David Schiminovich / Columbia University

Event Details / Abstract: Galaxies grow and quench by exchanging gas and energy with their circumgalactic medium (CGM), the diffuse atmospheres that fuel star formation and absorb feedback. In this talk I trace this exchange in three parts. First, I revisit scaling relations among stellar mass, size, star formation rate (SFR), and gas across cosmic time, including new JWST results on the SFR surface density sequence and associated selection effects. Next, I present recent work with the Circumgalactic Hα Spectrograph (CHaS), a narrowband integral field spectrograph (R~10,000) we built for the MDM Observatory on Kitt Peak to map faint Hα emission from the CGM of nearby galaxies. These maps reveal complex halo dynamics. Looking ahead, CHaS will continue to target the Local Sheet, where constrained Local Group simulations suggest that our sheet-like neighborhood channels accretion along preferred directions. Finally, I describe the “+”: new instruments and technologies, on the ground and in space, that can detect these faint signals and disentangle the processes that regulate star formation, disk growth, and quenching.