Unexpected Observations of Tidal Disruption Events: Diversity and a Preference for E+A Galaxies

TYPEAstrophysics Seminar
Speaker:Iair Arcavi
Organizer:Hagai Perets
Time:14:30 - 15:30
Location:Lidow 620
Abstract:A Tidal Disruption Event (TDE) happens to a star which gets close enough to a supermassive black-hole that it is torn apart by gravitational tidal forces. Optical (and possibly also high-energy) flares are thought to accompany such events, but the expected observational signature is still a topic of debate. The best observed optical/UV TDE candidate (Gezari et al. 2012, Nature), surprisingly showed no hydrogen (but only helium) in its spectrum, contrary to previous expectations. I will present the results of an archival search for TDEs in the Palomar Transient Factory database, where we find three such events - one similar to the Gezari et al. (He-rich) TDE, and two which do display hydrogen. Also, we find that these events show a preference for rare post-starburst (E+A) galaxies.