相关论文: The Highest Dynamical Frequency in the Inner Regio…
The kHz QPOs observed in a neutron star low mass X-ray binary are likely to be produced in the innermost regions of accretion disk around the neutron star. The rotational dynamics of the inner disk can be characterized by the presence of…
We apply the global mode analysis, which has been recently developed for the modeling of kHz quasi-periodic oscillations (QPOs) from neutron stars, to the inner region of an accretion disk around a rotating black hole. Within a…
The Accretion-Ejection Instability has been proposed to explain the low frequency Quasi-Periodic Oscillation (QPO) observed in low-mass X-Ray Binaries, in particular Black-Hole candidates. Its frequency, typically a fraction of the…
The observational characteristics of quasi-periodic oscillations (QPOs) from accreting neutron stars strongly indicate the oscillatory modes in the innermost regions of accretion disks as a likely source of the QPOs. The inner regions of…
Kilohertz quasi-periodic oscillations (kHz QPOs) are probably caused by matter in Keplerian orbit at some preferred radius in the accretion disc around a compact star. In a given source, QPO frequencies can drift by a few hundred Hz…
The correlation between the frequency and the absolute value of the frequency derivative of the kilohertz QPOs observed for the first time from 4U 1636-53 is a simple consequence and indicator of the existence of a non-Keplerian rotation…
Non-linear acoustic coupling of modes in accretion disks allows a parametric resonance between epicyclic motions. In black hole disks, such a resonance first occurs, and is strongest, when the radial and vertical epicyclic frequencies are…
In X-ray binaries, the frequencies revealed in X-ray quasi-periodic oscillations (QPOs) are often interpreted as characteristic frequencies in the inner accretion disk, though the exact oscillation mechanism is unknown at present. Broadened…
We analysed all archival RXTE observations of the neutron-star low-mass X-ray binary 4U 1636-53 up to May 2010. In 528 out of 1280 observations we detected kilohertz quasi-periodic oscillations (kHz QPOs), with ~ 65% of these detections…
Change of sign of the LNRF-velocity gradient has been found for accretion discs orbiting rapidly rotating Kerr black holes with spin a > 0.9953 for Keplerian discs and a > 0.99979 for marginally stable thick discs. Aschenbach (2004) has…
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.\,,…
We consider time-dependent models for rotating accretion flows onto black holes, where a transition takes place from an outer cooling-dominated disc to a radiatively inefficient flow in the inner region. In order to allow for a transition…
The physical origin of high-frequency QPOs (HFQPOs) in black-hole X-ray binaries remains an enigma despite many years of detailed observational studies. Although there exists a number of models for HFQPOs, many of these are simply "notions"…
When an accreting star is close to rotational equilibrium between the dipole component of the stellar magnetic field and the accretion disk, the star's rotation rate is roughly of the order of the Keplerean rotation rate at the inner…
Origin of wide varieties of quasi-periodic oscillation (QPO) observed in compact sources is still not well established. Its frequencies range from mHz to kHz spanning all compact objects. Are different QPOs, with different frequencies,…
Since the discovery of kHz quasi-periodic oscillations (QPO) in neutron star binaries, the difference between peak frequencies of two modes in the upper part of the spectrum, i.e. Delta (omega)=omega_h-omega_K has been studied extensively.…
The observed quasi-periodic oscillations (QPOs) in low-mass X-ray binaries have been suggested to be probably related to the characteristic oscillation modes in the inner part of a relativistic accretion disk. In this paper we study the…
It has recently been suggested that the maximum observed quasi-periodic oscillation (QPO) frequencies, $\nu_{max}$, for several low-mass X-ray binaries, particularly 4U 1820-30, correspond to the orbital frequency at the inner-most stable…
The shocked wave created on the accretion disk after different physical phenomena (accretion flows with pressure gradients, star-disk interaction etc.) may be responsible observed Quasi Periodic Oscillations (QPOs) in $X-$ray binaries. We…
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…