Related papers: Evolution of the bursting-layer wave during a Type…
The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. However, with only three giant flares ever recorded, and only two with data of sufficient quality to…
We have carried out a systematic study of the properties of the kilo-Hertz quasi-periodic oscillations (QPO) observed in the X-ray emission of the neutron star low-mass X-ray binary 4U1608-52, using archival data obtained with the Rossi…
Quasi-periodic oscillation (QPO) signals are discovered in some fast radio bursts (FRBs) such as FRB 20191221A, as well as in the X-ray burst associated with the galactic FRB from SGR 1935+2154. We revisit the intermediate-field FRB model…
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…
We consider torsional oscillations that are trapped in a layer of spherical-hole (bubble) nuclear structure, which is expected to occur in the deepest region of the inner crust of a neutron star. Because this layer intervenes between the…
Quasi-Periodic Oscillations (QPOs) observed during Soft Gamma Repeaters giant flares are commonly interpreted as the torsional oscillations of magnetars. The oscillatory motion is influenced by the strong interaction between the shear modes…
In the last few years, a mysterious new class of astrophysical objects has been uncovered. These are spatially coincident with the nuclei of external galaxies and show X-ray variations that repeat on timescales of minutes to a month. They…
The discovery of quasi-periodic brightness oscillations (QPOs) in the X-ray emission accompanying the giant flares of the soft gamma-ray repeaters SGR 1806-20 and SGR 1900+14 has led to intense speculation about their nature and what they…
Heyl (2000) made an interesting suggestion that the observed shifts in QPO frequency in type I X-ray bursts could be influenced by the same geometrical effect of strong gravity as the one that causes centrifugal force reversal discovered by…
X-ray quasi-periodic oscillations (QPOs) are commonly observed in Galactic X-ray binaries (XRBs) and extragalactic ultraluminous X-ray sources (ULXs). In this study, we perform a phase-resolved analysis of recently discovered X-ray…
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…
A number of black hole X-ray transients show quasi-periodic oscillations (QPOs) in the optical (ultraviolet) and X-ray bands at the same frequency, which challenge models for production of radiation at these wavelengths. We propose a model…
We report on an RXTE/PCA observation of Aql X-1 during its outburst in March 1997 in which, immediately following a Type-I burst, the broad-band 2-10 keV flux decreased by about 10% and the kilohertz QPO frequency decreased from 813+-3 Hz…
There have been many efforts to explain the dynamical mechanisms behind the phenomenology of quasi-periodic oscillations (QPOs) seen in the X-ray light curves of low-mass X-ray binaries. Up to now, none of the models can successfully…
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 studied the millihertz quasi-periodic oscillation (mHz QPO) in the 2020 outburst of the Be/X-ray binary 1A 0535+262 using Insight-HXMT data over a broad energy band. The mHz QPO is detected in the 27-120 keV energy band. The QPO centroid…
We construct a two-zone model to describe H and He burning on the surface of an accreting neutron star and use it to study the triggering of type I X-ray bursts. Although highly simplified, the model reproduces all of the bursting regimes…
Quasi-Periodic Erupters (QPEs) are a remarkable class of objects exhibiting very large amplitude quasi-periodic X-ray flares. Although numerous dynamical models have been proposed to explain them, relatively little attention has been given…
The Quasi-Biennial Oscillation (QBO) is understood to result from wave-mean-flow interactions, but the reasons for its relative stability remain a subject of ongoing debate. In addition, consensus has yet to be reached regarding the…
Be/X-ray binary pulsars show transient outbursts and complex timing behaviour, including millihertz quasi-periodic oscillations (QPOs), whose physical origin and energy dependence remain poorly understood. We aim to characterise the…