Black Hole Feedback in Galaxy Mergers with Vivian U

This colloquium was originally recorded on Thursday, August 22, 2024. Our Colloquium series is for physicists, by physicists. Please see our "Public Lecture" playlists for videos intended for the general public.
Galaxies, termed “Cosmic Ecosystems”, consist of stars, gas, and black holes - the interaction among which dictates how a galaxy grows over time as a dynamic entity. Existing theoretical models of feedback offer a basis for how stars and black holes enrich the chemical content of the gas reservoir and/or eject it out of the galaxy through winds. Galactic outflows driven by active supermassive black holes, particularly prevalent in interacting galaxy systems, tend to stop future generations of stars from being formed and drastically alter the fate of the host when star formation is quenched. The details of this active galactic nucleus (AGN) feedback process, which is thought to play a significant role in galaxy evolution across cosmic time, have been difficult to verify observationally.
In this talk, I will showcase new JWST and Keck integral-field spectroscopic observations of merging galaxies that trace the movement of the multiphase gas as it traverses the galactic ecosystems, enabling a detailed understanding of this dynamic feedback process. Our early results reveal galactic-scale shocks from starburst-driven superwinds, AGN outflows driven by precessing radio jets, and decelerating winds with signatures of ionization stratification. The power of resolved studies in dissecting how systems dynamically evolve has become indispensable for understanding multiphase gas feedback from nuclear to galactic scales.
Vivian U is an observational astronomer at the University of California, Irvine. She received her bachelor’s degree in Astrophysics from Caltech and PhD in Astronomy from the University of Hawaii at Manoa. She is currently a co-chair of the Habitable Worlds Observatory AGN Working Group and a member of the NASA Cosmic Origins AGN Science Interest Group Leadership Council. She also leads the extragalactic science team within the Far-InfraRed Spectroscopy Space Telescope collaboration, a probe mission concept designed to address high priority science questions identified in the National Academies’ 2020 Decadal Survey in Astronomy and Astrophysics. Vivian was a recipient of the 2020 AAAS Newcomb Cleveland Prize, and was named a National Academy of Sciences Kavli Frontiers of Science Fellow in 2019. She was featured on PBS NOVA in the Episode “New Eye on the Universe”, and will be a speaker at the TEDxManhattanBeach event this November.