RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 28 February 2019, 11:30-12:00; CSO Common Room

Francesco D'Eugenio

"Evidence of compaction in post-starburst galaxies at redshift 1"

Quiescent galaxies are on average smaller than star-forming galaxies of the same mass. This structural difference could be due either to the evolution of galaxy populations as a whole, or to the structural evolution of individual galaxies as they become quiescent. Gas rich mergers are effective at driving gas in the central region of galaxies, where it can trigger both star-formation and active galactic nuclei activity: as a consequence, galaxies that experienced major gas-rich mergers may both shrink in size and become quiescent. We use 0.6 < z < 1.0 visible rest-frame spectroscopy from the LEGA-C Survey to study the stellar population of post-starburst galaxies. In these systems, which have recently become quiescent, we find that stellar age increases with radius, as expected after major gas-rich mergers.