The quasi-periodic oscillations (QPOs) in black hole (BH) systems with different scales are interpreted based on the magnetic reconnection of large-scale magnetic fields generated by toroidal electric currents flowing in the inner region of the accretion disk, where the current density is assumed to be proportional to the mass density of the accreting plasma. The magnetic connection (MC) is taken into account in resolving dynamic equations describing the accretion disk, in which the MC between the inner and outer disk regions, between the plunging region and the disk, and between the BH horizon and the disk are involved. It turns out that a single QPO frequency associated with several BH systems with different scales can be fitted by invoking the magnetic reconnection due to the MC between the inner and outer regions of the disk, including the BH binaries XTE J1859+226, XTE J1650-500 and GRS 1915+105 and the massive BHs in NGC 5408 X-1 and RE J1034+396. In addition, the X-ray spectra corresponding to the QPOs for these sources are fitted based on the typical disk-corona model.
Chang-Yin HuangDing-Xiong WangJiu-Zhou WangZhi-Yun Wang
A model of low-frequency quasi-periodic oscillations(LFQPOs) of black hole X-ray binaries(BHXBs) is proposed based on the perturbed magnetohydrodynamic equations of an accretion disk.It turns out that the LFQPO frequencies of some BHXBs can be fitted by the frequencies of the toroidal Alfve'n wave oscillation corresponding to the maximal radiation flux.In addition,the positive correlation of the LFQPO frequencies with the radiation flux from an accretion disk is well interpreted.
Zhi-Yun WangChang-Yin HuangDing-Xiong WangJiu-Zhou Wang
We propose a two-component jet model consistent with the observations of several gamma ray bursts (GRBs) and active galactic nuclei (AGNs). The jet consists of inner and outer components, which are supposed to be driven by the Blandford- Znajek (BZ) and Blandford-Payne (BP) processes, respectively. The baryons in the BP jet are accelerated centrifugally via the magnetic field anchored in the accretion disk. The BZ jet is assumed to be entrained in a fraction of accreting matter leaving the inner edge of the accretion disk, and the baryons are accelerated in the conversion from electromagnetic energy to kinetic energy. By fitting the Lorentz factors of some GRBs (GRB 030329, GRB 051221A and GRB 080413B) and AGNs (Cen A, Mkn 501 and Mkn 421) with this model, we constrain the physical parameters related to the accretion and outflow of these two kinds of objects. We conclude that the spine/sheath structure of the jet from these sources can be interpreted naturally by the BZ and BP processes.
Wei XieWei-Hua LeiYuan-Chuan ZouDing-Xiong WangQingwen WuJiu-Zhou Wang
