Related papers: Trapped Disk Oscillations and Stable QPOs in Micro…
In the context of black hole spin in X-ray binaries, we propose that certain type of quasi-period oscillations (QPOs) observed in the light curves of black hole binaries (BHBs) are produced by X-ray modulation at the precession frequency of…
High-frequency quasi-periodic oscillations detected in the light curves of black hole candidates can, according to one model, be identified with hydrodynamic oscillations of the accretion disc. We describe a non-linear coupling mechanism,…
Observations of X-ray emissions from binary systems have always been considered important tools to test the validity of General Relativity in strong-field regimes. The pairs and triplets of high frequency quasi-periodic oscillations…
We consider the situation where a spin-induced wavy perturbation is present on disks of neutron-star low-mass X-ray binaries. By non-linearly coupling with the perturbation, some modes of disk oscillations resonantly interact with the…
We will summarize results of calculations of the modes of oscillation trapped within the inner region of accretion disks by the strong-field gravitational properties of a black hole (or a compact, weakly-magnetized neutron star). Their…
Recent results on the inner disk oscillations found in GRS 1915+105 are reviewed. QPOs during the low state are used as a marker for such oscillations and the physical picture emerging from a combined X-ray spectral and timing analysis is…
Observations of X-ray emissions from binary systems have long since been considered important tools to test General Relativity in strong-field regimes. The high frequency quasi-periodic oscillations (HFQPOs) observed in binaries containing…
High-frequency quasi-periodic oscillations (QPOs) appear in general-relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around rapidly rotating black holes (BHs). We perform polarized radiative transfer…
While the dynamical origin of the variability observed in Galactic Black hole systems, such as quasi-periodic oscillations (QPOs), are still a matter of debate, insight into the radiative components responsible for such behaviour can be…
Observations from the Rossi X-Ray Timing Explorer have shown the existence of high frequency quasi-periodic oscillations (HFQPOs) in the X-ray flux from accreting black hole binary systems. In at least two systems, these HFQPOs come in…
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 present a study of the properties of strong 0.8-3.0 Hz quasi-periodic oscillations (QPOs) that occurred during 1997 RXTE observations of the microquasar GRS 1915+105 in the low-hard state. The high count rates allow us to track…
Microquasars are the compact objects generally including accreting black holes which produce relativistic jets. The physical mechanisms of jet launching, collimation, and acceleration are poorly understood. Microquasars show strong…
We explore some properties of twin kilohertz quasiperiodic oscillations (QPOs) in a simple toy-model consisting of two oscillation modes coupled by a general nonlinear force. We examine resonant effects by slowly varying the values of the…
The study of quasi-periodic oscillations (QPOs) of X-ray flux observed in many microquasars can provide a powerful tool for testing of the phenomena occurring in strong gravity regime. QPOs phenomena can be well related to the oscillations…
We ascribe the interpretation of the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to MHD Alfven wave oscillations in the different mass density regions of the accreted matter at…
In this work, we study the correlation between Quasi-periodic Oscillation (QPO) frequency and the spectral parameters during various X-ray states in the black hole binary GRS 1915+105 which matches well with the predicted relativistic…
Kilohertz quasi-periodic oscillations (QPOs) in low-mass X-ray binaries (LMXBs) may represent the orbital frequencies of the innermost Keplerian orbits around accreting neutron stars. Attempts have recently been made to derive constraints…
We have discovered a ~1 Hz quasi-periodic oscillation (QPO) in the persistent-emission, the dips, and the type I X-ray bursts of the low-mass X-ray binary 4U 1323-62. The rms amplitude of the QPO is approximately 9%, only weakly depending…
We have investigated properties of the Quasi Periodic Oscillation (QPO) features in the accretion powered X-ray pulsar Cen X-3 over a period of about four years using observations carried out with the Proportional Counter Array (PCA) of the…