活躍星系核中的潮汐瓦解事件

活躍星系核中的潮汐瓦解事件


Seminar:- Tidal Disruption Events in Active Galactic Nuclei 

A fraction of tidal disruption events(TDEs) occur in active galactic nuclei (AGNs) whose black holes possess accretion disks; these TDEs can be confused with common AGN flares. The disruption itself is unaffected by the disk, but the evolution of the bound debris stream is modified by its collision with the disk when it returns to pericenter. The outcome of the collision is largely determined by the ratio of the stream mass current to the azimuthal mass current of the disk rotating underneath the stream footprint, which in turns depends on the mass and luminosity of the AGN.

To characterize TDEs in AGNs, we simulated a suite of stream-disk collisions with various mass current ratios. The collision excites shocks in the disk, leading to inflow and energy dissipation orders of magnitude above Eddington. However, much of the radiation is trapped in the inflow and advected into the black hole, so the actual luminosity may be closer to Eddington. The rapid inflow causes the disk interior to the impact point to be depleted within a fraction of the mass return time. If the stream is heavy enough to penetrate the disk, part of the outgoing material eventually hits the disk at larger radii, dissipating its kinetic energy there; another part becomes unbound, emitting synchrotron radiation as it shocks with surrounding gas. 
 
時間:2019.07.12(五) 14:30
地點:香港大學 莊月明物理樓522室
講者:陳志豪 博士 Dr. Chi-Ho Chan(Racah Institute of Physics, Hebrew University of Jerusalem and School of Physics and Astronomy, Tel Aviv University)
語言:英語

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