Query : 2004A&A...427..251G

2004A&A...427..251G - Astronomy and Astrophysics, volume 427, 251-261 (2004/11-3)

Excitation of low-frequency QPOs in black hole accretion.


Abstract (from CDS):

We study possible mechanisms of excitation of quasiperiodic oscillations in the accretion flow of black hole accreters in their hard spectral states, in the context of the ``truncated disk'' model. Quasi-spherical oscillations of the inner ion-supported accretion flow (ISAF) can be excited by the interaction of this hot flow with the cool disk extending outward from it. The fundamental mode of (p-mode) oscillation is most easily excited, and has a frequency near the Kepler frequency at the inner edge of the cool disk. The strongest excitation mechanism is a feedback loop involving cooling of the ISAF by soft photons from the cool disk and heating of the cool disk by the ISAF, while synchrotron emission can be a relatively strong damping effect. Growth times are computed by detailed Comptonization calculations of the interaction of an idealized ISAF with a cool disk. Typical growth times as short as a few dynamical times are found, while amplitudes can be as large as 10%.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - black hole physics - radiation mechanisms: non-thermal - X-rays: stars

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* KV UMa HXB 11 18 10.7930420496 +48 02 12.314730120     12.25     K5V-M1V 802 0
2 V* V381 Nor HXB 15 50 58.6637920704 -56 28 35.258385000   17.95 16.6     K3III 1146 0
3 HD 226868 HXB 19 58 21.6757355952 +35 12 05.784512688 9.38 9.72 8.91 8.42   O9.7Iabpvar 4268 0

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