2019年9月18日, 星期三

Informal TDLI Astrophysics Seminar (05.08/2019) Black-hole discoseismic oscillations and instabilities in eccentric astrophysical discs

Description

 

Speaker: Janosz Dewberry (University of Cambridge)
 
Time: 1:30 pm  May 8 (Wednesday)
Location: Meeting Room 202, Tsung-Dao Lee Institute (East wing of Pao Yue-Kong Library)
 
Abstract:
High-frequency, quasi-periodic oscillations (HFQPOs) observed in the emission from galactic black hole binaries present an important but unresolved problem in astrophysics. An attractive explanation offered by hydrodynamic theory involves the excitation of `discoseismic' oscillations in the inner regions of a black hole accretion disk, where they are confined by relativistic effects. However, magnetic fields can significantly alter the dynamics of such pulsations, which additionally require a driving mechanism to reach observable amplitudes. I present a magnetohydrodynamic analysis of the effects of magnetic fields with different geometries on so-called trapped inertial waves, and numerical simulations exhibiting the modes' excitation to large amplitudes through non-linear coupling with eccentric disk deformations. I additionally  present preliminary results regarding more fundamental aspects of both global mode and local wave excitation in eccentric discs.
 
Bio:
Janosz Dewberry works on various problems on astrophysical accretion disks.
He will receive his Ph.D. in the May from DAMTP at University of Cambridge.
He will join T.D.Lee Institute as a postdoctoral fellow in Fall 2019.

Location information

上海交通大学闵行校区

Country
中国
County
上海市
City
闵行区 200240
Street
800号 东川路

上海交通大学闵行校区