Friday, October 12, 2018
2:00 pm
Cahill Center for Astronomy and Astrophysics – Cahill Center for Astronomy and Astrophysics

TAPIR Seminar

QPOs, global modes and magnetized discs
Janosz Dewberry, Graduate Student, Department of Applied Maths and Theoretical Physics, Cambridge University

The 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 `diskoseismic' 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.

*** NOTE UNUSUAL VENUE:   312 CAHILL ***
Contact JoAnn Boyd joann@caltech.edu at 4280
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