Past Event

Tidal disruption events and their host galaxies: an explanation for the post-starburst overrepresentation

November 3, 2022
4:05 PM - 4:35 PM
Pupin 1402

Seminar by Elisa Bortolas, University of Milan

A tidal disruption event (TDE) occurs when a star is destroyed by the strong tidal shear of a massive black hole (MBH). TDE detections can unveil otherwise dormant MBHs, and they constitute unique probes for constraining the MBH demographics, especially in the low-mass end of the MBH mass function. The accumulation of TDE observations over the last years has revealed that post-starburst galaxies -- rare objects in the local Universe -- are significantly overrepresented in the sample of TDE hosts, but the reason for this remains debated. In my presentation, I will show that this fact is naturally explained if the TDE rates are computed accounting for a complete stellar mass function, instead of the generally used monochromatic population of one-solar-mass stars. In particular, the starburst that forms the nuclear star cluster results in an initially large TDE rate that quickly drops at later times; this significant drop cannot be reproduced when assuming a monochromatic stellar population. I will conclude my presentation by discussing the critical importance of accounting for a complete stellar mass function to reconcile theoretically predicted and observed TDE rates even in quiescent galaxies.

Host: Zoltan Haiman