Carnegie Mellon University

Astro Seminar

Bold Nuclei in Old Galaxies

The evolution of galaxies is fundamentally connected to the evolution of their central black holes. The large-scale environment of the host galaxy's gas reservoir, star formation rate, and merger history affect the rate at which stars and gas can be accreted onto the central supermassive black hole. In response, accretion energy can regulate and ultimately drive the end of star formation in these host galaxies. The accretion of individual stars by supermassive black holes can be observed through tidal disruption events (TDEs). A disproportionate number of TDEs are found in post-starburst (or E+A) galaxies, suggesting a new connection between the pc-scale dynamics of a galaxy and it’s star formation history on kpc scales. Post-starburst galaxies are also the sites of possible black hole accretion feedback, as the depletion of their molecular gas reservoirs are delayed into this phase. I will present recent work on what the cause of the TDE rate enhancement during this phase may be and how this host galaxy preference can be used as a tool for identifying new TDEs. I will also present work on how the molecular gas properties of galaxies evolve after a starburst and the possibilities for how AGN feedback might act to quench galaxies and remove their star-forming gas reservoirs.