MG12 - Talk detail
 

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 Participant 

Institution

Session

Talk

Abstract

Excitation of Diskoseismic Oscillations in Black-Hole Accretion Disks: Super-reflection, Corotation Amplifier and QPOs

I will discuss recent works on the wave dynamics of accretion disk around a black hole, focusing on global disk instabilities and (inertial-acoustic) wave modes trapped in the inner disk region. I will explain the role of wave super-reflection and corotation amplifier, as well as how general relativistic effects help to drive these modes overstable. Applications to the quasi-periodic oscillations obsereved in accreting black hole systems (X-ray binaries and AGNs) will also be discussed.

Excitation of Diskoseismic Oscillations in Black-Hole Accretion Disks: Super-reflection, Corotation Amplifier and QPOs

I will discuss recent works on the wave dynamics of accretion disk around a black hole, focusing on global disk instabilities and (inertial-acoustic) wave modes trapped in the inner disk region. I will explain the role of wave super-reflection and corotation amplifier, as well as how general relativistic effects help to drive these modes overstable. Applications to the quasi-periodic oscillations obsereved in accreting black hole systems (X-ray binaries and AGNs) will also be discussed.

Effects of Magnetic Fields on the Diskoseismic Modes of Accreting Black Holes

Hydrodynamical disk oscillations have been invoked to explain quasi-periodic variabilities observed in a number of accreting black hole X-ray binaries and AGNs. We study how magnetic fields affect these modes. We show that even a weak (sub-thermal) magnetic field can modify or ``destroy'' the self-trapping zone of some of the (otherwise promising) disk modes (so-called g-modes), while other modes (p-modes) are more robust and may survive in a turbulent, magnetic disk. We also discuss some new results concerning the instabilities of magnetic, rotating flows.

Tidal Excitations of Neutron Star Oscillation Modes in Coalescing Compact Binaries

In a coalesing neutron star (NS) binary, various oscillation modes of the NS can be resonantly excited by the tidal force of the companion in the last few minutes prior to binary merger. This can affect the orbital decay rate and the gravitational waveforms. We review our current understanding of resonant excitations of f, g, and inertial (including Rossby) modes and show that under certain conditions they may leave their inprints on the binary inspiral waveforms and provide a new tool to study NS oscillations. Similar, but much larger effects in compact binaries containing white dwarfs, relevant to LISA, will also be discussed.

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