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Explaining the 'Outliers' Track in Black Hole X-ray Binaries with a BZ-Jet and Inner-Disk Coupling 期刊论文  OAI收割
UNIVERSE, 2022, 卷号: 8, 期号: 6, 页码: 13
作者:  
Chang, Ning;  Liu, Xiang;  Xie, Fu-Guo;  Cui, Lang;  Shan, Hao
  |  收藏  |  浏览/下载:31/0  |  提交时间:2022/10/13
Synchronous X-ray/Optical QPOs from the Black Hole LMXB MAXI J1820+070 期刊论文  OAI收割
Monthly Notices of the Royal Astronomical Society, 2021
作者:  
HXMT
  |  收藏  |  浏览/下载:52/0  |  提交时间:2022/02/08
black hole physics  Low Mass X-ray Binaries  accretion  accretion  discs  stars: individual (MAXI J1820+070)  Astrophysics - High Energy  Astrophysical Phenomena  Abstract: We present high-speed optical photometry from SAAO and SALT on the black hole LMXB MAXI J1820+070 (ASSASN-18ey), some of it simultaneous with NICER, Swift and Insight-HXMT X-ray coverage. We detect optical Quasi-Periodic Oscillations (QPOs) that move to higher frequencies as the outburst progresses, tracking both the frequency and evolution of similar X-ray QPOs previously reported. Correlated X-ray/optical data reveal a complex pattern of lags, including an anti-correlation and a sub-second lag that evolve over the first few weeks of outburst. They also show correlated components separated by a lag equal to the QPO period roughly centered on zero lag, implying that the inter-band variability is strongly and consistently affected by these QPOs at a constant phase lag of roughly ±Ю The synchronisation of X-ray and optical QPOs indicates that they must be produced in regions physically very close to each other  we thus propose that they can be explained by a precessing jet model, based on analogies with V404 Cyg and MAXI J1348-630.  
An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文  OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者:  
HXMT
  |  收藏  |  浏览/下载:59/0  |  提交时间:2022/02/08
accretion  accretion disks  black hole physics  X-rays: binaries  time  Astrophysics - High Energy Astrophysical Phenomena  Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.
  
Timing analysis of Swift J1658.2-4242's outburst in 2018 with Insight-HXMT, NICER and AstroSat 期刊论文  OAI收割
Journal of High Energy Astrophysics, 2019, 卷号: 24, 页码: 30-40
作者:  
HXMT
  |  收藏  |  浏览/下载:57/0  |  提交时间:2022/02/08
Accretion  accretion disks  Black hole physics  X-rays: binaries:  Swift J1658.2-4242  Astrophysics - High Energy Astrophysical Phenomena  Abstract: We present the observational results from a detailed timing analysis of the black hole candidate Swift J1658.2-4242 during its 2018 outburst with the observations of Hard X-ray Modulation Telescope (Insight-HXMT), Neutron Star Interior Composition Explorer (NICER) and AstroSat in 0.1-250 keV. The evolution of intensity, hardness and integrated fractional root mean square (rms) observed by Insight-HXMT and NICER are presented in this paper. Type-C quasi-periodic oscillations (QPOs) observed by NICER (0.8-3.5 Hz) and Insight-HXMT (1-1.6 Hz) are also reported in this work. The features of the QPOs are analyzed with an energy range of 0.5-50 keV. The relations between QPO frequency and other characteristics such as intensity, hardness and QPO rms are carefully studied. The timing and spectral properties indicate that Swift J1658.2-4242 is a black hole binary system. Besides, the rms spectra of the source calculated from the simultaneous observation of Insight-HXMT, NICER and AstroSat support the Lense-Thirring origin of the QPOs. The relation between QPO phase lag and the centroid frequency of Swift J1658.2-4242 reveals a near zero constant when < 4Hz and a soft phase lag at 6.68 Hz. This independence follows the same trend as the high inclination galactic black hole binaries such as MAXI J1659-152.  
Effect of non-stationary accretion on spectral state transitions: An example of a persistent neutron star LMXB 4U 1636-536 期刊论文  OAI收割
RESEARCH IN ASTRONOMY AND ASTROPHYSICS, 2018, 卷号: 18, 期号: 3
作者:  
Zhang Hui;  Yu WenFei
  |  收藏  |  浏览/下载:17/0  |  提交时间:2021/12/06
A Monte Carlo study of the spectra from inhomogeneous accretion flow 期刊论文  OAI收割
RESEARCH IN ASTRONOMY AND ASTROPHYSICS, 2017, 卷号: 17, 期号: 8
作者:  
Yu XiaoDi;  Li YaPing;  Xie FuGuo;  Ma RenYi
  |  收藏  |  浏览/下载:19/0  |  提交时间:2021/12/06
Hot Accretion Flows Around Black Holes 期刊论文  OAI收割
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, VOL 52, 2014, 卷号: 52, 页码: 529-588
作者:  
Yuan, Feng;  Narayan, Ramesh;  Faber, SM;  VanDishoeck, E
收藏  |  浏览/下载:25/0  |  提交时间:2015/08/04