We study spectral and temporal properties of Galactic short orbital period transient black hole XTE J1118+480 during its 2005 outburst using archival data of RXTE PCA and HEXTE instruments in the combined energy range...We study spectral and temporal properties of Galactic short orbital period transient black hole XTE J1118+480 during its 2005 outburst using archival data of RXTE PCA and HEXTE instruments in the combined energy range of 3−100 keV.Spectral analysis with the physical two component advective flow(TCAF)model allows us to understand the accretion flow properties of the source.We found that this outburst of XTE J1118+480 is an unconventional outburst as the source was only in the hard state(HS).Our spectral analysis suggests that during the entire outburst,the source was highly dominated by the low angular momentum sub-Keplerian halo rate.Since the source was active in radio throughout the outburst,we make an effort to estimate X-ray contribution of jets to total observed X-ray emissions from the spectral analysis with the TCAF model.The total X-ray intensity shows a similar nature of evolution as that of radio and jet X-ray fluxes.This allowed us to define this‘outburst’also as a jet dominated‘outburst’.Total X-ray flux is also found to subside when jet activity disappears.Our detailed spectral analysis also indicated that although the source was only in the HS during the outburst,in the late declining phase the spectrum became slightly softer due to the slow rise in the Keplerian disk rate.展开更多
The radiative mechanism of black hole X-ray transients （BHXTs） in their quiescent states （defined as the 2-10 keV X-ray luminosity ≤ 10^34 erg s-1） remains unclear. In this work, we investigate the quasi-simultan...The radiative mechanism of black hole X-ray transients （BHXTs） in their quiescent states （defined as the 2-10 keV X-ray luminosity ≤ 10^34 erg s-1） remains unclear. In this work, we investigate the quasi-simultaneous quiescent state spectrum （including radio, infrared, optical, ultraviolet and X-ray） of two BHXTs, A0620-00 and XTE J1118＋480. We find that these two sources can be well described by a coupled accretion - jet model. More specifically, most of the emission （radio up to infrared, and the X-ray waveband） comes from the collimated relativistic jet. Emission from hot accretion flow is totally insignificant, and it can only be observed in mid-infrared （the synchrotron peak）. Emission from the outer cold disk is only evident in the UV band. These results are consistent with our previous investigation on the quiescent state of V404 Cyg and confirm that the quiescent state is jet-dominated.展开更多
We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when ...We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when the source was in a transition from the hard state to the soft state. The photon spectra can be well fit- ted with a phenomenological model of a power-law/cutoff power-law and a physical model of bulk-motion Comptonization. The spectral properties smoothly evolve away from the hard state and then stay in the soft state. The fitting results of the physical model reveal the peak of the burst had a flux of 2.90 × 10-8 erg cm-2 s-1 in the 2–100 keV energy range and was observed on 2001 Sep. 9; it transitioned to the hard state. The total flux decays by a factor of ～3 as it evolves into the soft state. The photon index Γ increases from ～1.5 in the hard state and stays at ～2.5 in the soft state. We found that the effective area of the high-energy X-ray emission region （the Compton cloud） decreases, i.e. the area of the Compton cloud decreases by a factor of ～23 during the transition from the hard state to the soft state. Combining the new radio and quasi-periodic oscillation studies, the model of total flux in the 2–100 keV energy range, the jet emission and the timing analysis during the state transition, we suggest a possible geometry and evolution for the （jet＋corona＋disk） system, like that proposed by Kalemci et al. based on enhanced lags and peak frequency shift during the transition.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
The quasi-periodic oscillations （QPOs） in black hole （BH） systems with different scales are interpreted based on the magnetic reconnection of large-scale mag- netic fields generated by toroidal electric currents f...The quasi-periodic oscillations （QPOs） in black hole （BH） systems with different scales are interpreted based on the magnetic reconnection of large-scale mag- netic 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 be- tween 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 in- voking 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.展开更多
基金This work made use of PCA and HEXTE data of NASA’s RXTE satellite.Research of D.D.and S.K.C.is supported in part by the Higher Education Dept.of the Govt.of West Bengal,India.D.D.and S.K.C.also acknowledge partial support from ISRO sponsored RESPOND project(ISRO/RES/2/418/17-18)fund.D.C.and D.D.acknowledge support from DST/SERB sponsored Extra Mural Research project(EMR/2016/003918)+2 种基金fund.A.J.and D.D.acknowledge support from DST/GITA sponsored India-Taiwan collaborative project(GITA/DST/TWN/P-76/2017)fund.A.J.acknowledges CSIR SRF fellowship(09/904(0012)2K18 EMR-1)post-doctoral fellowship of PRL,Ahmedabad,India.K.C.acknowledges support from DST/INSPIRE fellowship(IF 170233).
文摘We study spectral and temporal properties of Galactic short orbital period transient black hole XTE J1118+480 during its 2005 outburst using archival data of RXTE PCA and HEXTE instruments in the combined energy range of 3−100 keV.Spectral analysis with the physical two component advective flow(TCAF)model allows us to understand the accretion flow properties of the source.We found that this outburst of XTE J1118+480 is an unconventional outburst as the source was only in the hard state(HS).Our spectral analysis suggests that during the entire outburst,the source was highly dominated by the low angular momentum sub-Keplerian halo rate.Since the source was active in radio throughout the outburst,we make an effort to estimate X-ray contribution of jets to total observed X-ray emissions from the spectral analysis with the TCAF model.The total X-ray intensity shows a similar nature of evolution as that of radio and jet X-ray fluxes.This allowed us to define this‘outburst’also as a jet dominated‘outburst’.Total X-ray flux is also found to subside when jet activity disappears.Our detailed spectral analysis also indicated that although the source was only in the HS during the outburst,in the late declining phase the spectrum became slightly softer due to the slow rise in the Keplerian disk rate.
基金supported by the National Basic Research Program of China(973 Program,Grant 2014CB845800)the National Natural Science Foundation of China(Grant Nos.11203057,11103061,11133005 and 11121062)the Strategic Priority Research Program“The Emergence of Cosmological Structures”of the Chinese Academy of Sciences(Grant XDB09000000)
文摘The radiative mechanism of black hole X-ray transients （BHXTs） in their quiescent states （defined as the 2-10 keV X-ray luminosity ≤ 10^34 erg s-1） remains unclear. In this work, we investigate the quasi-simultaneous quiescent state spectrum （including radio, infrared, optical, ultraviolet and X-ray） of two BHXTs, A0620-00 and XTE J1118＋480. We find that these two sources can be well described by a coupled accretion - jet model. More specifically, most of the emission （radio up to infrared, and the X-ray waveband） comes from the collimated relativistic jet. Emission from hot accretion flow is totally insignificant, and it can only be observed in mid-infrared （the synchrotron peak）. Emission from the outer cold disk is only evident in the UV band. These results are consistent with our previous investigation on the quiescent state of V404 Cyg and confirm that the quiescent state is jet-dominated.
基金partially supported by the Grant-in-Aid for Scientific Research on Priority Areas (Grant No. 14079101)financial supports from the National Natural Science Foundation of China (Grant No. 10778702)+1 种基金the National Basic Research Program of China (973 Program, Grant No. 2009CB824800)the Policy Research Program of Chinese Academy of Sciences (KJCX2-YWT24)
文摘We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when the source was in a transition from the hard state to the soft state. The photon spectra can be well fit- ted with a phenomenological model of a power-law/cutoff power-law and a physical model of bulk-motion Comptonization. The spectral properties smoothly evolve away from the hard state and then stay in the soft state. The fitting results of the physical model reveal the peak of the burst had a flux of 2.90 × 10-8 erg cm-2 s-1 in the 2–100 keV energy range and was observed on 2001 Sep. 9; it transitioned to the hard state. The total flux decays by a factor of ～3 as it evolves into the soft state. The photon index Γ increases from ～1.5 in the hard state and stays at ～2.5 in the soft state. We found that the effective area of the high-energy X-ray emission region （the Compton cloud） decreases, i.e. the area of the Compton cloud decreases by a factor of ～23 during the transition from the hard state to the soft state. Combining the new radio and quasi-periodic oscillation studies, the model of total flux in the 2–100 keV energy range, the jet emission and the timing analysis during the state transition, we suggest a possible geometry and evolution for the （jet＋corona＋disk） system, like that proposed by Kalemci et al. based on enhanced lags and peak frequency shift during the transition.
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 the Central Universities (HUST: 2011TS159)
文摘The quasi-periodic oscillations （QPOs） in black hole （BH） systems with different scales are interpreted based on the magnetic reconnection of large-scale mag- netic 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 be- tween 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 in- voking 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.
