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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:19/0  |  提交时间:2022/10/13
A study on the hysteresis effect and spectral evolution in the mini-outbursts of balck hole X-ray binary XTE J1550-564 期刊论文  OAI收割
Frontiers in Astronomy and Space Sciences, 2021, 卷号: 8, 页码: 37
作者:  
Dong, Ai-Jun;  Liu, Chang;  Ge, Kang;  Liu, Xiang;  Zhi, Qi-Jun
  |  收藏  |  浏览/下载:19/0  |  提交时间:2022/06/30
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:41/0  |  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.  
Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite 期刊论文  OAI收割
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY, 2020, 卷号: 63, 期号: 4, 页码: 18
作者:  
Zhang, Shuang-Nan;  Li, TiPei;  Lu, FangJun;  Song, LiMing;  Xu, YuPeng
  |  收藏  |  浏览/下载:53/0  |  提交时间:2021/12/06
Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite 期刊论文  OAI收割
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY, 2020, 卷号: 63, 期号: 4, 页码: 18
作者:  
Zhang, Shuang-Nan;  Li, TiPei;  Lu, FangJun;  Song, LiMing;  Xu, YuPeng
  |  收藏  |  浏览/下载:46/0  |  提交时间:2021/12/06
Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT 期刊论文  OAI收割
Journal of High Energy Astrophysics, 2020, 卷号: 27, 页码: 51-52
作者:  
HXMT
  |  收藏  |  浏览/下载:36/0  |  提交时间:2022/02/08
Astrophysics - High Energy Astrophysical Phenomena  Abstract: Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in X-rays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. This allows, in particular, to observe bright sources like X-ray binaries (XRBs) in their bright/outburst states with high cadence and high statistics at hard and soft X-rays at once. It was then expected that the Insight-HXMT mission will bring us new insights regarding the characteristics of several source classes. Examples include characterizing High-Mass X-ray Binaries (HMXBs) and the outburst evolution of Low-Mass X-ray Binaries (LMXBs). For instance, in HMXB systems, the region around their Alfven radius that is responsible to determine whether accretion or propeller occurs, or the region around the NS magnetic pole where the intense X-rays are supposed to be produced are specially appealing targets of study. For the LMXBs, the evolution the outburst and the properties of the compact objects themselves are obvious priority targets for Insight-HXMT. Due to the broad coverage in energy, Insight-HXMT is specially well suited to study the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environment.  
Insight-HXMT observations of Swift J0243.6+6124: the evolution of RMS pulse fractions at super-Eddington luminosity 期刊论文  OAI收割
Monthly Notices of the Royal Astronomical Society, 2020, 卷号: 497, 页码: 5498-5506
作者:  
HXMT
  |  收藏  |  浏览/下载:36/0  |  提交时间:2022/02/08
stars: neutron  pulsars: individual: Swift J0243.6+6124  X-rays:  binaries  Astrophysics - High Energy Astrophysical Phenomena  Abstract: Based on Insight-HXMT data, we report on the pulse fraction evolution during the 2017-2018 outburst of the newly discovered first Galactic ultraluminous X-ray (ULX) source Swift J0243.6+6124. The pulse fractions of 19 observation pairs selected in the rising and fading phases with similar luminosity are investigated. The results show a general trend of the pulse fraction increasing with luminosity and energy at supercritical luminosity. However, the relative strength of the pulsation between each pair evolves strongly with luminosity. The pulse fraction in the rising phase is larger at luminosity below 7.71 × 1038 erg s-1, but smaller at above. A transition luminosity is found to be energy independent. Such a phenomenon is first confirmed by Insight-HXMT observations and we speculate that it may have relation with the radiation-pressure-dominated accretion disc.  
Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文  OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者:  
HXMT
  |  收藏  |  浏览/下载:35/0  |  提交时间:2022/02/08
Insight-HXMT  Geant4 simulation  Background observation  Astrophysics  - Instrumentation and Methods for Astrophysics  Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation  (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.  
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:46/0  |  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.
  
Formation of accreting millisecond X-ray pulsars 期刊论文  OAI收割
RESEARCH IN ASTRONOMY AND ASTROPHYSICS, 2019, 卷号: 19, 期号: 8, 页码: 11
作者:  
He X(贺祥);  Meng XC(孟祥存);  Chen HL(陈海亮)
  |  收藏  |  浏览/下载:48/0  |  提交时间:2019/10/21