Related papers: Predicting spin of compact objects from their QPOs…
Previous analysis of AstroSat observations of the black hole system MAXI J1535-571, have revealed the presence of a strong Quasi-Periodic Oscillation (QPO) whose frequency is correlated with the high energy spectral index. Here, we fit the…
We numerically analyze quasiperiodic oscillations (QPOs) using a well-established spacetime model with neutron star sources. Within the framework of general relativity, we present expressions for the fundamental frequencies of test…
We report transient quasi-periodic oscillations (QPOs) on minute timescales in relativistic, radiative models of the galactic center source Sgr A*. The QPOs result from nonaxisymmetric $m=1$ structure in the accretion flow excited by MHD…
Quasi-periodic oscillations (QPOs) are coherent peaks of variability power observed in the X-ray power spectra (PSDs) of stellar mass X-ray binaries (XRBs). A scale invariance of the accretion process implies they should be present in the…
Twin quasi-periodic millisecond modulations of the X-ray flux (kHz QPOs) have recently been reported from an accreting 2.5 ms X-ray pulsar. We identify modes of disk oscillations whose frequencies are in agreement with the observed ones…
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 variability properties of accreting compact objects predicted by dynamical models are characterized by a number of distinct frequencies that are specific to each model. Because the accretion disks around neutron stars and black holes…
This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is…
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…
Low frequency (approximately 0.1-35 Hz) quasi-periodic oscillations (QPO) of the X-ray flux characterize many of the black hole candidates, in particular those which have radio evidence for jets. These QPO have amplitudes of up to 20 per…
Quasi-periodic oscillations (QPOs) observed in the power spectrum of black holes are unique observational probes to the background spacetime since they can be directly related to the timescales associated with the motion of matter orbiting…
We report the detection of a short-lived narrow quasi-periodic oscillation (QPO) at ~88 mHz in an Insight-HXMT observation during the soft state of the persistent black hole high mass X-ray binary Cygnus X-1. This QPO is significantly…
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…
Quasi-periodic oscillations (QPOs) at frequencies near 1000 Hz were recently discovered in several x-ray binaries containing neutron stars. Two sources show no correlation between QPO frequency and source count rate (Berger et al. 1996,…
Context. Quasi-periodic oscillations (QPOs) are a common feature of the power spectrums of X-ray binaries. Currently it is not possible to unambiguously differentiate the large number of proposed models to explain these phenomena through…
Quasi-periodic oscillation (QPO) detected in the X-ray radiation of black hole X-ray binaries (BHXBs) is thought to originate from dynamical processes in the close vicinity of the black holes (BHs), and thus carries important physical…
Quasi-periodic X-ray brightness oscillations (QPOs) with frequencies around a kilohertz have now been discovered in more than a dozen neutron stars in low-mass X-ray binary systems using the Rossi X-ray Timing Explorer. There is strong…
KHz QPOs have now been detected in more than twenty accreting neutron stars in low-mass binary systems. Two kHz QPOs are usually detected in each star. Burst oscillations and two kHz QPOs have recently been detected in the 401 Hz…
We report the discovery with the proportional counter array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) of a 450 Hz quasiperiodic oscillation (QPO) in the hard X-ray flux from the galactic microquasar GRO J1655-40. This is the…
The numerical investigation of Bondi-Hoyle accretion onto a moving black hole has a long history, both in Newtonian and in general-relativistic physics. By performing new two-dimensional and general-relativistic simulations onto a rotating…