Probing super-Eddington accretion via tidal disruption events

A star wandering too close to a massive black hole can be torn apart by the tidal force of the black hole. Such a tidal disruption event (TDE) illuminates a massive black hole for about a year. In the first few months, stellar material can be supplied to the black hole at a rate greatly exceeding the Eddington accretion rate, giving us a perfect window to peek into super-Eddington accretion. The understanding of super-Eddington accretion has important implications for black hole growth and galaxy evolution in the early universe. In this talk, I will first give a summary of the observational status of TDEs. Then I will introduce the basics of TDE physics and present our theoretical calculations on what are the key parameters leading to super-Eddington TDEs. Lastly, I will talk about our 3D general relativistic radiation magnetohydrodynamics simulations of super-Eddington accretion disks in the context of TDEs. The results of these simulations provide us answers to some puzzles posed by TDE observations, and can be applied to study other super-Eddington astrophysical systems.

Lixin Dai
Speaker Introduction: 

Dr. Lixin Dai received her B.S. in Physics and Mathematics from the Hong Kong University of Science and Technology in 2005, and her Ph.D. in Physics from Stanford University in 2012. She was a joint postdoctoral fellow of Yale University and University of Chile for two years, and since then she has been a postdoctoral associate at the University of Maryland and a scientist at the Joint Space-Science Institute. Dr. Dai’s main research area is theoretical and computational high-energy astrophysics, especially on black hole accretion and jet physics, tidal disruption events, and X-ray binaries. She also works on high-energy astro-particle physics and gravitational waves. 

KIAA-PKU Auditorium
Eric Peng
Wednesday, February 22, 2017 - 4:00pm to 5:00pm