An unusual timing and spectral state of a black hole microquasar XTE J1550- 564 observed with RXTE is analyzed. Millisecond variabilities are found, which are significantly shorter than the minimum possible time scale...An unusual timing and spectral state of a black hole microquasar XTE J1550- 564 observed with RXTE is analyzed. Millisecond variabilities are found, which are significantly shorter than the minimum possible time scale in the light curves of black hole binaries, as suggested by Sunyaev ＆ Revnivtsev （2000）. The X-ray spectral fitting result indicates that there is an unusual soft component in the spectrum, which may be responsible for the millisecond variabilities. The millisecond variabilities as well as the unusual soft spectral component should be produced from some small, but independent active regions in the accretion disk.展开更多
A new approach of detecting the black hole spin in x-ray binaries is proposed based on the model of the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes, in which the BZ process is use...A new approach of detecting the black hole spin in x-ray binaries is proposed based on the model of the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes, in which the BZ process is used to power the jet emissions from x-ray binaries, and high frequency quasi-periodic oscillations （QPOs） are explained by a rotating hotspot in the inner region of the accretion disc surrounding a fast-spinning black hole. It is shown that the black hole spins of several x-ray binaries （XTE J1550-564, GRO d1665-40 and GRS 1915＋105） can be constrained in a rather narrow range, provided that QPOs and jets coexist in these sources.展开更多
A model of low-frequency quasi-periodic oscillations （LFQPOs） of black hole X-ray binaries （BHXBs） is proposed based on the perturbed magnetohydrody- namic equations of an accretion disk. It turns out that the LFQ...A model of low-frequency quasi-periodic oscillations （LFQPOs） of black hole X-ray binaries （BHXBs） is proposed based on the perturbed magnetohydrody- namic equations of an accretion disk. It turns out that the LFQPO frequencies of some BHXBs can be fitted by the frequencies of the toroidal Alfv6n wave oscillation cor- responding 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.展开更多
Correlations of active galactic nuclei （AGNs） with microquasars are discussed based on the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes （CEBZMC） in black hole （BH） accretion ...Correlations of active galactic nuclei （AGNs） with microquasars are discussed based on the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes （CEBZMC） in black hole （BH） accretion disk. The proportions of several quantities of BH systems for both AGNs and microquasars are derived by combining the observational data with CEBZMC. It is shown that the square of the magnetic field at the BH horizon is inversely proportional to the BH mass, while the accretion rate of the disk is proportional to the BH mass. In addition, the very steep emissivity indexes from the recent XMM-Newton observations of the nearby bright Seyfert 1 galaxy MCG-6-30-15 and the microquasars XTE J1650-500 are well fitted by considering the MC effects on the disk radiation. These results suggest strongly the correlations of A GNs with microquasars.展开更多
基金Supported by the National Natural Science Foundation of China.
文摘An unusual timing and spectral state of a black hole microquasar XTE J1550- 564 observed with RXTE is analyzed. Millisecond variabilities are found, which are significantly shorter than the minimum possible time scale in the light curves of black hole binaries, as suggested by Sunyaev ＆ Revnivtsev （2000）. The X-ray spectral fitting result indicates that there is an unusual soft component in the spectrum, which may be responsible for the millisecond variabilities. The millisecond variabilities as well as the unusual soft spectral component should be produced from some small, but independent active regions in the accretion disk.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10173004, 10373006 and 10121503.
文摘A new approach of detecting the black hole spin in x-ray binaries is proposed based on the model of the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes, in which the BZ process is used to power the jet emissions from x-ray binaries, and high frequency quasi-periodic oscillations （QPOs） are explained by a rotating hotspot in the inner region of the accretion disc surrounding a fast-spinning black hole. It is shown that the black hole spins of several x-ray binaries （XTE J1550-564, GRO d1665-40 and GRS 1915＋105） can be constrained in a rather narrow range, provided that QPOs and jets coexist in these sources.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11173011,11143001,11103003 and 11045004)the National Basic Research Program of China (973 Program,2009CB824800)the Fundamental Research Funds for theCentral Universities (HUST:2011TS159)
文摘A model of low-frequency quasi-periodic oscillations （LFQPOs） of black hole X-ray binaries （BHXBs） is proposed based on the perturbed magnetohydrody- namic equations of an accretion disk. It turns out that the LFQPO frequencies of some BHXBs can be fitted by the frequencies of the toroidal Alfv6n wave oscillation cor- responding 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.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10373006 and 10121503
文摘Correlations of active galactic nuclei （AGNs） with microquasars are discussed based on the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes （CEBZMC） in black hole （BH） accretion disk. The proportions of several quantities of BH systems for both AGNs and microquasars are derived by combining the observational data with CEBZMC. It is shown that the square of the magnetic field at the BH horizon is inversely proportional to the BH mass, while the accretion rate of the disk is proportional to the BH mass. In addition, the very steep emissivity indexes from the recent XMM-Newton observations of the nearby bright Seyfert 1 galaxy MCG-6-30-15 and the microquasars XTE J1650-500 are well fitted by considering the MC effects on the disk radiation. These results suggest strongly the correlations of A GNs with microquasars.
