YITP WORKSHOP ON
Quasi-Periodic Oscillations and Time Variabilities of Accretion Flows
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ABSTRACT

NAME
INSTITUTE
TITLE OF THE TALK
Y. Kato
Tsukuba Univ., Japan
Magnetohydrodynamic Studies of Quasi-Periodic Oscillations in Accretion Flows around Black Holes
Quasi-periodic X-ray brightness oscillations (QPOs) have been observed in many X-ray binaries including neutron star (NS) and black hole (BH) candidates. After the discoveries of twin peak QPOs in both NS and BH systems, many interpretations of QPOs in the context of disk oscillations have been developed. Within the framework of resonant disk oscillation models, frequencies of QPOs are regulated by the mass and the spin of the central object. This is why QPOs are believed to be a powerful tool to investigate a nature of accretion disk in the vicinity of black holes and neutron stars. In spite of many three-dimensional (3-D) magnetohydrodynamic (MHD) simulations on accretion flows plunging into black holes having been performed by many groups, MHD studies on disk oscillations have been poorly understood.
In my talk, we review our findings on QPOs in 3-D MHD simulations of accretion disks and discuss the origin of such oscillations. We also introduce on our recent findings of variable emissions in MHD accretion disks.


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