Related papers: Interpreting black hole QPOs
In our previous work (Paper I) we applied several models of high-frequency quasi-periodic oscillations (HF QPOs) to estimate the spin of the central compact object in three Galactic microquasars assuming the possibility that the central…
During its 2003 outburst, the black-hole X-ray transient H1743-322 produced two-sided radio and X-ray jets. Applying a simple and symmetric kinematic model to the trajectories of these jets, we determine the source distance, 8.5 \pm 0.8…
High frequency quasi-periodic oscillations (HF QPOs) appear in the X-ray variability of several accreting low-mass binaries. In a series of works it was suggested that these QPOs may have connection to inhomogeneities orbiting close to an…
The global nonlinear time-dependent evolution of the inertial-acoustic mode instability in accretion disks surrounding black holes has been investigated. The viscous stress is assumed to be proportional to the gas pressure only, i.e.\,,…
In the resonance model, high-frequency quasi-periodic oscillations (QPOs) are supposed to be a consequence of nonlinear resonance between modes of oscillations occurring within the innermost parts of an accretion disk. Several models with a…
Quasi-periodic oscillations (QPOs) are often present in the X-ray flux from accreting stellar-mass black holes (BHs). If they are due to relativistic (Lense-Thirring) precession of an inner accretion flow which is misaligned with the disc,…
We generalize the effective point particle approach to black hole dynamics to include spin. In this approach dissipative effects are captured by degrees of freedom localized on the wordline. The absorptive properties of the black hole are…
Recent studies have shown that strong correlations are observed between low frequency QPO`s and the spectral power law index for a number of black hole candidate sources (BHC's), when these sources exhibit quasi-steady hard x-ray emission…
The high-frequency quasi-periodic oscillations in the X-ray emission of black hole binaries and candidates are briefly examined with respect to the question of X-ray states. We use the prescription of McClintock and Remillard (2005), in…
We interpret the correlation over five orders of magnitude between high frequency and low frequency in a quasi-periodic oscillations (QPO) found by Psaltis, Belloni & van der Klis (1999) for black hole (BH), neutron star (NS) systems and…
Variable features in black hole X-ray Binaries (BH-XRBs) are observed in different energy ranges and time scales. The physical origin of different spectral states in BH-XRBs and their relations with the underlying accretion disc are still…
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…
Given the peculiar and (in spite of many efforts) unexplained quasi-periodic oscillation (QPO) twin peak phenomena in accretion disc PSD observations, the present exploratory analytical article tries to inquire deeper into the relationship…
We briefly review the properties and physical consequences of quasiperiodic oscillations (QPOs) seen on many occasions in the X-ray emission from black-hole binary systems. We also report on the discovery of QPOs at 164 and 328 Hz in…
We examine the possibility that hyper-accretion onto newly born, black holes occurs in highly intermittent, non-asymmetric fashion favorable to gravitational wave emission in a neutrino cooled disk. This picture of near-hole accretion is…
The astrophysical origins of the binary black hole systems seen with gravitational waves are still not well understood. However, features in the distribution of black-hole masses, spins, redshifts, and eccentricities provide clues into how…
We have studied quasinormal modes of spinor $\frac{1}{2}$, massless Dirac field perturbations of a black hole in massive gravity. The parameters of the theory, such as the mass of the black hole, the scalar charge of the black hole, mode…
The quasi-periodic oscillations (QPOs) observed in the X-ray variability of both black hole (BH) and neutron star (NS) systems provide a tool for probing strong gravity and dense matter equations of state. Nevertheless, the mechanism of QPO…
We study the quasi-periodic oscillations from the accretion disk around the distorted Schwarzschild black hole in the framework of the resonant models. We confine ourselves to the case of a quadrupole distortion which can be caused for…
The two established techniques for measuring black hole spin in X-ray binaries often yield conflicting results, which must be resolved before either method may be deemed robust. In practice, black hole spin measurements based on fitting the…