11:45 am–12:45 pm ERC 401
Host: Michael D. Gladders
Gourav Khullar (University of Pittsburgh) "Catching galaxies napping with JWST: Stochastic Star Formation Histories in Post-Starburst Galaxies at Redshift > 4-6"
This talk will lay out the discovery and characterization of mini-quenched (or napping) galaxies at high redshifts, and the characterization of their stochastic star formation histories. JWST spectroscopic surveys are discovering mini-quenched galaxies when sampling the first billion years of the Universe’s evolution. These spectra show a UV upturn, weak Balmer break, and weak or non-existent emission lines, all indicating a lull period in star formation, a recent star formation episode, and significant mass assembly in the past. This channel of mass assembly has serious implications for how compact galaxies at high redshifts form and evolve, and deserves a detailed characterization of global and local properties of stellar populations. In this talk, I will unpack the physical conditions of the stellar populations in napping/mini-quenched galaxies at z > 4 with the UNCOVER survey (JWST Cycle 1 GO program; PIs: Bezanson, Labbe) using spectrophotometric stellar population synthesis modeling. I will also show our team’s work with post-starburst strong gravitationally lensed galaxies discovered in the COOL-LAMPS and SGAS surveys, both based at UChicago (e.g., COOL J1241+2219 at redshift 5, JWST Cycle 1 GO 2566: PI: Khullar), in order to identify old stellar populations and comprehensively characterize local star formation histories with IFU spectroscopy. Finally, I will place these studies in the context of unpacking galaxy assembly in a diversity of mass ranges at high redshifts, especially using samples of gravitationally lensed galaxies with the LEGGOS survey.
