Related papers: Re-estimating the Spin Parameter of the Black Hole…

Estimations of black hole spin in the three Galactic microquasars GRS 1915+105, GRO J1655-40, and XTE J1550-564 have been carried out based on spectral and timing X-ray measurements and various theoretical concepts. Among others, a…

The black hole X-ray binary (BHXRB) Swift J151857.0-572147 was discovered during its first outburst in March 2024. We review the archive of NICER observations from this outburst, focusing on the soft states. We select spectra for which the…

We determined the spin value of supermassive black hole (SMBH) in active galactic nuclei (AGN) with investigated ultraviolet-to-optical spectral energy distribution, presented in the sample of Shang et al. (2005). The estimates of the spin…

Compact binary coalescences are the most promising sources of gravitational waves (GWs) for ground based detectors. Binary systems containing one or two spinning black holes are particularly interesting due to spin-orbit (and eventual…

We model the binary black hole system OJ287 as a spinning primary and a non-spinning secondary. It is assumed that the primary has an accretion disk which is impacted by the secondary at specific times. These times are identified as major…

The construction of initial data for black-hole binaries usually involves the choice of free parameters that define the spins of the black holes and essentially the eccentricity of the orbit. Such parameters must be chosen carefully to…

It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole…

The peaks of the spectra of the accretion disks surrounding massive black holes in quasars are in the far-UV or soft X-ray band, which are usually not observed. However, in the disk corona model, the soft photons from the disk are…

We propose a new method for black hole spin measurement. In this method, we consider a gas blob or ring falling onto a black hole from the marginally stable orbit, keeping its initial orbital angular momentum. We calculate the gas motion…

We present a spectral analysis of a black hole X-ray binary XTE J2012+381 during its 2022 outburst, using data from NICER and AstroSat. Combining data from NICER, LAXPC20, and SXT, we extract energy spectra covering the 0.7-10.0 keV range.…

The black hole mass and spin estimates assuming various specific models of the 3:2 high frequency quasi-periodic oscillations (HF QPOs) have been carried out in Torok et al. (2005, 2011). Here we briefly summarize some current points.…

We fit X-ray reverberation models to Rossi X-ray Timing Explorer data from the X-ray binary Cygnus X-1 in its hard state to yield estimates for the black hole mass and the distance to the system. The rapid variability observed in the X-ray…

Context: Cygnus X-1 is a black hole X-ray binary system in which the black hole captures and accretes gas from the strong stellar wind emitted by its supergiant O9.7 companion star. The irradiation of the supergiant star essentially…

The origin of the spins of stellar-mass black holes is still controversial, and angular momentum transport inside massive stars is one of the main sources of uncertainty. Here, we apply hierarchical Bayesian inference to derive constraints…

Emission from within the plunging region of black hole accretion flows has recently been detected in two X-ray binary systems. There is, furthermore, a possible discrepancy between the inferred spins of gravitational wave and…

The strong-field region inside a black hole needs special attention during numerical simulation. One approach for handling the problem is the moving puncture method, which has become an important tool in numerical relativity since it allows…

We study conformally-flat initial data for an arbitrary number of spinning black holes with exact analytic solutions to the momentum constraints constructed from a linear combination of the classical Bowen-York and conformal Kerr extrinsic…

We present results of recurrence analysis of the black hole X-ray binary Cygnus X-1 using combined observations from the Rossi X-ray Timing Explorer All-sky Monitor and the Japanese Monitor of All-sky X-ray Image aboard the ISS. From the…

We study identical mass black hole binaries with spins perpendicular to the binary's orbital plane. These binaries have individual spins ranging from $s/m^2=-0.90$ to 0.90, ($s_1 = s_2$ in all cases) which is near the limit possible with…

We present a survey of how the spectral features of black hole X-ray binary systems depend on spin, accretion rate, viewing angle, and Fe abundance when predicted on the basis of first principles physical calculations. The power law…