Related papers: Quasi-periodic oscillations under wavelet microsco…
Recent discoveries from time-domain surveys are defying our expectations for how matter accretes onto supermassive black holes (SMBHs). The increased rate of short-timescale, repetitive events around SMBHs, including the newly-discovered…
We analyze the time variability of the X-ray emission of RE J1034+396 -- an active galactic nucleus with the first firm detection of a quasi-periodic oscillations (QPO). Based on the results of a wavelet analysis, we find a drift in the QPO…
Using two-dimensional hydrodynamic simulations, we investigate the stability of shocked accretion flows around black holes under non-axisymmetric perturbations. By systematically exploring the parameter space of specific energy and angular…
Low and intermediate frequency quasi-periodic oscillations (QPOs) are thought to be due to oscillations of Comptonizing regions or hot regions embedded in Keplerian discs. Observational evidence of evolutions of QPOs would therefore be very…
Quasi-Periodic Oscillations (QPOs) are very puzzling since they remain totally unexplained by popular earlier models of accretion disks. The significant rms value in power density spectrum implies that the oscillation involves in the…
We study the Rossby wave instability model of high-frequency quasi-periodic oscillations (QPO) of microquasars. We show ray-traced light curves of QPO within this model and discuss perspectives of distinguishing alternative QPO models with…
A kilohertz quasi-periodic oscillation (kHz QPO) is an observationally robust high-frequency timing feature detected from neutron star low-mass X-ray binaries (LMXBs). This feature can be very useful to probe the superdense core matter of…
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…
We examine the properties of the viscous dissipative accretion flow around rotating black holes in presence of mass loss. Considering thin disc approximation, we self-consistently calculate the inflow-outflow solutions and observe that the…
The X-ray light curves of accreting black holes and neutron stars in binary systems show various types of quasi-periodic oscillations (QPOs), the origin of which is still debated. The Relativistic Precession Model identifies the QPO…
We present analysis of fast variability of Very Large Telescope/ISAAC (infra-red), \textit{XMM-Newton}/OM (optical) and EPIC-pn (X-ray), and RXTE/PCA (X-ray) observations of the black hole X-ray binary GX 339-4 in a rising hard state of its…
We show that the low frequency QPO seen in the power density spectra of black hole binaries (and neutron stars) can be explained by Lense-Thirring precession. This has been proposed many times in the past, and simple, single radius models…
Frequencies of the three quasi-periodic oscillation (QPO) modes observed simultaneously in the accreting black hole GRO J1655-40 are compared with the predictions of models. Models in which all three QPO signals are produced at the same…
The quasi-periodic oscillations (QPOs) in black hole (BH) systems of different scales are interpreted based on the magnetic reconnection of the large-scale magnetic fields generated by the toroidal electric currents flowing in the inner…
We present a comprehensive analysis of Low Frequency Quasi-periodic Oscillation (LFQPO) associated time-lags in the persistently variable black hole binary GRS 1915+105 using 441 ks of \textit{AstroSat} observations from March 2016 to March…
A remarkable correlation between the centroid frequencies of quasi periodic oscillations, QPOs, (or peaked noise components) from low mass X-ray binaries, has been recently discovered by Psaltis, Belloni and van der Klis (1999). This…
We present a detailed analysis of the evolution of type-C quasiperiodic oscillations (QPOs) observed during the flaring state of the recently discovered black hole X-ray binary Swift J1727.8-1613, utilizing data from the Insight Hard X-ray…
We report the discovery of a quasi-periodic oscillation (QPO) in data obtained with the Rossi X-ray Timing Explorer of the dipping and eclipsing low-mass X-ray binary EXO 0748-676. The QPO had a frequency between 0.58 and 2.44 Hz changing…
Astrophysical black hole candidates are thought to be the Kerr black hole predicted by General Relativity. In order to confirm the Kerr-nature of these objects, we need to probe the geometry of the space-time around them and see if the…
The Galactic black hole (BH) X-ray binary 4U 1630-47 went into a new outburst in 2021 after $\sim$ 600 days from its 2020 outburst. We perform a detailed analysis of quasi-periodic oscillations and spectral evolutions during its 2021…