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A First Characterization of Tidal Disruption Events and Their Surprising Properties

Event Details

Event Dates: 

Monday, November 13, 2017 - 4:00pm

Seminar Location: 

  • JILA Auditorium

Speaker Name(s): 

Iair Arcavi

Speaker Affiliation(s): 

University of California, Santa Barbara
Seminar Type/Subject

Scientific Seminar Type: 

  • Astrophysical & Planetary Sciences Seminar

Event Details & Abstract: 

The search for the tidal disruptions of stars by supermassive black holes (tidal disruption events; TDEs) is now yielding exciting results. In recent years, both gamma- and x-ray candidates as well as optical+UV events have been discovered, and a tantalizing connection to extreme coronal light emitters has been made. It is still not clear what the connection between these very different types of TDE candidates is, but recently we were able to tie several of the optical+UV events together into a coherent class of outbursts. This picture immediately offered two new insights. First, TDE emission properties are not as expected - our set of objects which all peak in the near UV rather than the expected x-rays, show lower than expected velocities and span an unexplained continuum of spectral classes from H-rich to H-poor. The second insight relates to the host galaxies - optical+UV TDEs show a strong (200x!) and unexpected preference for post-starburst galaxies. The reason for this is still not clear. We are collecting more and more observations of TDEs as they are discovered by wide field transient surveys and by our own first- ever specialized survey for TDEs. Understanding TDE emission properties and their peculiar host galaxy preference has far reaching implications for studying quiescent massive black holes, accretion physics and galaxy dynamics.