A5072494183- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Mechanics and Biomechanics Studies
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
- Particle Detector Development and Performance
- Astronomical Observations and Instrumentation
- Experimental and Theoretical Physics Studies
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Wind and Air Flow Studies
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Microbial infections and disease research
- Viral gastroenteritis research and epidemiology
- Prostate Cancer Diagnosis and Treatment
- Respiratory viral infections research
- Radiation Therapy and Dosimetry
- Advanced Radiotherapy Techniques
Southwest Minzu University
2025
Southwest Jiaotong University
2025
China Aerospace Science and Industry Corporation (China)
2025
Ministry of Agriculture and Rural Affairs
2025
Phillips Exeter Academy
2024
National Astronomical Observatories
2013-2023
Chinese Academy of Sciences
2015-2023
University of Chinese Academy of Sciences
2019-2023
University of Geneva
2016
National Institute for Astrophysics
2016
A typical galaxy is thought to contain tens of millions stellar-mass black holes, the collapsed remnants once massive stars, and a single nuclear supermassive hole. Both classes holes accrete gas from their environments. The accreting forms flattened orbiting structure known as an accretion disk. During past several years, it has become possible obtain measurements spins two by modeling X-ray emission disks. Two methods are employed, both which depend upon identifying inner radius disk with...
Cygnus X-1 is a binary star system that comprised of black hole and massive giant companion in tight orbit. Building on our accurate distance measurement reported the preceding paper, we first determine radius star, thereby constraining scale system. To obtain full dynamical model binary, use an extensive collection optical photometric spectroscopic data taken from literature. By using all available observational constraints, show orbit slightly eccentric (both radial velocity independently...
A heavy black hole in an x-ray binary If a interacts with companion star, the system emits x-rays and can form radio jet. The masses of holes these binaries are all lower than those detected using gravitational waves, challenging models formation from massive stars. Miller-Jones et al. used astrometry to refine distance Cygnus X-1, well-studied binary. They found larger previous estimates, raising mass 21 solar masses. results challenge wind loss rates implemented stellar evolution models....
The black hole binary system LMC X-3 has been observed by virtually every X-ray mission since the inception of astronomy. Among persistent sources, is uniquely both habitually soft and highly variable. Using a fully relativistic accretion disk model, we analyze hundreds spectra collected during eight missions that span 26 years. For selected sample 391 RXTE spectra, find to within ≈2% inner radius constant over time unaffected source variability. Even considering an ensemble missions,...
The compact primary in the X-ray binary Cygnus X-1 was first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, orbital inclination angle of binary. Building on these results, which are based our favored (asynchronous) model, we measured radius inner edge hole's accretion disk by fitting thermal continuum spectrum a fully relativistic model thin disk. Assuming that spin axis is aligned with angular momentum vector,...
We report a direct and accurate measurement of the distance to X-ray binary Cygnus X-1, which contains first black hole be discovered. The 1.86 (-0.11,+0.12) kpc was obtained from trigonometric parallax using Very Long Baseline Array. position measurements are also sensitive 5.6 d orbit we determine clockwise on sky. measured proper motion X-1 which, when coupled Doppler shift, gives three-dimensional space system. When corrected for differential Galactic rotation, non-circular (peculiar) is...
We measure the spin of XTE J1550−564 using two leading methods: (i) modelling thermal continuum spectrum accretion disc; and (ii) broad red wing reflection fluorescence Fe Kα line. find that these independent measurements are in agreement. For continuum-fitting analysis, we use a data sample consisting several dozen Rossi X-ray Timing Explorer spectra, for pair ASCA spectra from single epoch. Our estimate black hole primary method is −0.11 < a* 0.71 (90 per cent confidence), with most likely...
In Gou et al. (2011), we reported that the black hole primary in X-ray binary Cygnus X-1 is a near-extreme Kerr with spin parameter a*>0.95(3σ). We confirm this result while setting new and more stringent limit: a*>0.983 at 3σ(99.7%) level of confidence. The earlier work, which was based on an analysis all three useful spectra were then available, possibly biased by presence these relatively strong Compton power-law component: fraction thermal seed photons scattered into power law...
We analyze photometry of the soft X-ray transient A0620 − 00 spanning nearly 30 years, including previously published and unpublished data. Previous attempts to determine inclination using subsets these data have yielded a wide range measured values i. Differences in value i been due changes shape light curve uncertainty regarding contamination from disk. give new technique for estimating disk fraction find that is significant all curves, even infrared. also normalization originate variable...
The first extragalactic X-ray binary, LMC X-1, was discovered in 1969. In the 1980s, its compact primary established as fourth dynamical black hole candidate. Recently, we published accurate values for mass of and orbital inclination angle binary system. Building on these results, have analyzed 53 spectra obtained by RXTE and, using a selected sample 18 spectra, determined dimensionless spin parameter to be a* = 0.92+0.05−0.07. This result takes into account all sources observational...
We present a dynamical model of the high mass X-ray binary LMC X-1 based on high-resolution optical spectroscopy and extensive near-infrared photometry. From our new data we find an orbital period P = 3.90917 ± 0.00005 days. refined analysis All Sky Monitor from RXTE 3.9094 0.0008 days, which is consistent with period. A simple Thomson scattering in stellar wind can account for modulation seen light curves. The V − K color star (1.17 0.05) implies AV 2.28 0.06, much larger than previously...
eXTP is a science mission designed to study the state of matter under extreme conditions density, gravity and magnetism. Primary goals are determination equation at supra-nuclear measurement QED effects in highly magnetized star, accretion strong-field regime gravity. targets include isolated binary neutron stars, strong magnetic field systems like magnetars, stellar-mass supermassive black holes. The carries unique unprecedented suite state-of-the-art scientific instruments enabling for...
During its year-long outburst in 1975–76, the transient source A0620–00 reached an intensity of 50 Crab, all-time record for any X-ray binary. The has been quiescent since then. We have recently determined accurate values black hole (BH) mass, orbital inclination angle, and distance. Building on these results, we measured radius inner edge accretion disk around BH primary by fitting thermal continuum spectrum to our version relativistic Novikov–Thorne thin-disk model. thereby estimated spin...
Cygnus X-1 is a well-studied persistent black hole X-ray binary. Recently, the three parameters needed to estimate spin of this system, namely mass $M$, orbital inclination $i$ and source distance $D$, have been updated. In work we redetermine parameter using continuum-fitting technique for those updated values. Based on assumption that axis aligned with plane, fit thermal disk component fully relativistic thin accretion model. The error in arising from combined observational uncertainties...
Large-span roof structures are sensitive to wind loads, and the values taken by code usually cannot meet design requirements. By conducting scaled rigid model pressure tests on a large-span irregular in Xi'an, coefficients of cantilevered curved under different directions were systematically analyzed. The results show that is mainly subjected negative pressure, with local positive at eaves upper surface north building. Strong suction zones easily formed top south building structural strength...
Bleeding constitutes an essential stage in pre-processing operations for fish products. In China, this process remains entirely manual, characterized by low efficiency, high labor intensity, and operational hazards, creating a pressing demand versatile automated equipment the market. To address mechanization requirements efficient freshwater bloodletting, we developed bleeding machine based on gill-based blood extraction principles, incorporating impact-triggered positional methodology. The...
Abstract The basal stresses generated by rock avalanches, along with the resulting seismic signals, act as important indicators that provide insights into avalanche dynamics. Here, an experimental study on propagation behavior and dynamics of granular flows moving a 3D‐printed bumpy substrate was conducted stress signature responses were analyzed. results indicate agitating layer emerges in nearly steady state increasing particle size, characterized base‐normal velocity internal shear...
All prior work on measuring the spins of stellar-mass black holes via X-ray continuum-fitting method has relied use weakly-Comptonized spectra obtained in thermal dominant state. Using a self-consistent Comptonization model, we show that one can analyze exhibit strong power-law components and obtain values inner disk radius, hence spin, are consistent with those Specifically, many RXTE two hole transients, H1743-322 XTE J1550-564, demonstrate radius edge accretion remains constant to within...
We present results from a deep Suzaku observation of the black hole in LMC X-1, supplemented by coincident monitoring with Rossi X-ray Timing Explorer (RXTE). identify broad relativistic reflection features soft disc-dominated spectrum. A strong and variable power-law component emission is which we use to demonstrate that enhanced Comptonization strengthens disc reflection. constrain spin parameter modelling X-1's features. For our primary most comprehensive spectral model, obtain high value...
The iron line and the continuum-fitting methods are currently two leading techniques for measuring black hole spins with electromagnetic radiation. They can be naturally extended probing spacetime geometry around holes testing general relativity in strong field regime. In past couple of years, there has been significant work to use method test nature holes. this Letter, we show its capability constraining by analyzing 17 RXTE data X-ray binary LMC X-1.
MAXI J1803-298, a newly-discovered Galactic transient and black hole candidate, was first detected by \emph{MAXI}/GSC on May 1st, 2021. In this paper, we present detailed spectral analysis of J1803-298. Utilizing the X-ray reflection fitting method, perform joint fit to spectra respectively, observed \emph{NuSTAR} \emph{NICER}/XTI same day over energy range between 0.7-79.0 keV, found its spin (and inclination angle i) can be constrained close an extreme value, 0.991 ($i\sim$ $70 ^{\circ}$),...
4U 1543-47 is a low mass X-ray binary which harbours stellar-mass black hole located in our Milky Way galaxy. In this paper, we revisit 7 data sets were the Steep Power Law state of 2002 outburst. The spectra observed by Rossi Timing Explorer. We have carefully modelled reflection spectra, and made joint-fit to these with relxill, for reflected emission. found moderate spin, $0.67_{-0.08}^{+0.15}$ at 90% statistical confidence. Negative spins (< 0.5) more than 99% confidence are ruled out....
We present a dynamical study of the Galactic black hole binary system Nova Muscae 1991 (GS/GRS 1124-683). utilize 72 high resolution Magellan Echellette (MagE) spectra and strictly simultaneous V-band photometric observations; simultaneity is unique crucial feature this study. The data were taken on two consecutive nights cover full 10.4-hour orbital cycle. radial velocities secondary star are determined by cross-correlating object with best-match template spectrum obtained using same...