[1009.0157] Radiatively inefficient accretion flows induced by gravitational-wave emission before massive black hole coalescence

Authors: Kimitake Hayasaki (Department Astronomy, Kyoto University)

Date: 1 Sep 2010

Abstract: We study an accretion flow during the gravitational-wave driven evolution of binary massive black holes. After the binary orbit decays due to interacting with a massive circumbinary disk, the binary is decoupled from the circumbinary disk because the orbital-decay timescale due to emission of gravitational wave becomes shorter than the viscous timescale evaluated at the inner edge of circumbinary disk. During the subsequent evolution, the accretion disk, which is truncated at the tidal radius because of the tidal torque, also shrinks as the orbital decay. Assuming that the disk mass changed by this process is all accreted, the whole region of the disk completely becomes radiatively inefficient when the semi-major axis is several hundred Schwarzschild radii. The disk temperature can become comparable with the virial temperature there in spite of a low disk luminosity. The prompt high-energy emission is hence expected long before black hole coalescence as well as the gravitational wave signals. Binary massive black holes finally merge without accretion disks.

abs pdf

Sep 01, 2010

1009.0157 (/preprints)
2010-09-01, 23:32 [edit]

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