A model of rotating hotspots for the 3 : 2 frequency ratio of high-frequency quasi-periodic oscillations in black hole X-ray binaries

Authors: Wang, Ding-Xiong; Ye, Yong-Chun; Yao, Guo-Zheng; Ma, Ren-Yi

Source: Monthly Notices of the Royal Astronomical Society, Volume 359, Number 1, May 2005 , pp. 36-42(7)

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Abstract:

We propose a model to explain a puzzling 3 : 2 frequency ratio of high-frequency quasi-periodic oscillations (HFQPOs) in the black hole (BH) X-ray binaries, GRO J1655−40, GRS 1915+105 and XTE J1550−564. In our model, a non-axisymmetric magnetic coupling of a rotating BH with its surrounding accretion disc coexists with the Blandford–Znajek process. The upper frequency is fitted by a rotating hotspot near the inner edge of the disc, which is produced by the energy transferred from the BH to the disc. The lower frequency is fitted by another rotating hotspot somewhere away from the inner edge of the disc, which arises from the screw instability of the magnetic field on the disc. It turns out that the 3 : 2 frequency ratio of HFQPOs in these X-ray binaries could be well fitted to the observational data with a much narrower range of the BH spin. In addition, the spectral properties of HFQPOs are discussed. The correlation of HFQPOs with jets from microquasars is contained naturally in our model.

Keywords: accretion, accretion discs; black hole physics; instabilities; magnetic fields; stars: general

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1365-2966.2005.08846.x

Affiliations: 1: Department of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China

Publication date: 2005-05-01