Related papers: Quasi-periodic oscillations from Rossby Wave Insta…

We develop a simple physical model to describe the most common type of low-frequency quasi-periodic oscillations (QPOs) seen in a number of accreting black hole systems, as well as the shape of the relativistically broadened iron emission…

Three main types of low-frequency quasi-periodic oscillations (LFQPOs) have been observed in Black Hole Candidates. We re-analyzed RXTE data of the bright systems XTE J1859+226, XTE J1550-564 and GX 339-4, which show all three of them. We…

Low mass x-ray binaries (LMXBs), with either a neutron star (NS) or a black hole, show in their power spectra quasiperiodic oscillations (QPOs). Those at highest frequencies show up in pairs and are named twin peak high frequency QPOs (HF…

While there are many dynamical mechanisms and models that try to explain the origin and phenomenology of the quasi-periodic oscillations (QPOs) seen in the X-ray light curves of low-mass X-ray binaries, few of them address how the radiative…

We report the discovery with XMM-Newton of an approximately 7 mHz X-ray (0.3-10.0 keV) quasi-periodic oscillation (QPO) from the eclipsing, high-inclination black hole binary IC 10 X-1. The QPO is significant at > 4.33 sigma confidence…

We continue our earlier studies of quasi-periodic oscillations (QPOs) in the power spectra of accreting, rapidly-rotating black holes that originate from the geometric "light echoes" of X-ray flares occurring within the black hole…

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 present broadband ionospheric scintillation observations of highly defined symmetric quasi-periodic oscillations (QPO: Maruyama 1991) caused by plasma structures in the midlatitude ionosphere using the LOw Frequency ARray (LOFAR: van…

The low frequency quasi periodic oscillations (QPOs) are commonly observed during hard states of black hole binaries. Several studies have established various observational/empirical correlations between spectral parameters and QPO…

We present a systematic analysis of type C quasi-periodic oscillation (QPO) observations of H 1743--322 throughout the Rossi X-ray Timing Explorer (RXTE) era. We find that, while different outbursts have significant flux differences, they…

We suggest a possible explanation for the high frequency quasi-periodic oscillations (QPOs) in black hole low mass X-ray binaries. By solving the perturbation general relativistic magnetohydrodynamic equations, we find two stable modes of…

We report on the numerical discovery of quasi-periodic oscillations (QPOs) associated with accretion through a non-axisymmetric magnetic boundary layer in the unstable regime, when two ordered equatorial streams form and rotate…

Astronomy is presently experiencing profound growth in the deployment of machine learning to explore large datasets. However, transient quasi-periodic oscillations (QPOs) which appear in power density spectra of many X-ray binary system…

We investigate spectro-temporal properties for two black hole X-ray binary sources, MAXI J1535$-$571 and H 1743$-$322, during their hard and hard-intermediate states. For MAXI J1535$-$571, we analyze Swift/XRT, NuSTAR and NICER…

We report the discovery of quasi-periodic oscillations (QPO) at ~11 mHz in two RXTE observations and one Chandra observation of the black hole candidate H1743-322. The QPO is observed only at the beginning of the 2010 and 2011 outbursts at…

Since EXOSAT produced the first good quality X-ray light curves of Seyfert galaxies there have been several claims of quasi-periodic oscillations (QPOs). None of these have withstood repeated analyses and observations. We review some…

We report the discovery of strong aperiodic X-ray variability and quasi-periodic oscillation (QPO) in the X-ray light curves of a new X-ray Nova, XTE J1550-564, and the evolution of the observed temporal properties during the rise of the…

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…

We report the timing results with Insight-HXMT observations of X-ray binary IGR J19294+1816 during its 2019 Type I outburst at the decline phase shortly following its peak. We analyze the light curves and power density spectrum (PDS) of the…

Observations with RXTE (Rossi X-ray Timing Explorer) revealed the presence of High Frequency Quasi-Periodic Oscillations (HFQPOs) of the X-ray flux from several accreting stellar mass Black Holes. HFQPOs (and their counterparts at lower…