Related papers: The Global-Normal Disk Oscillations and the Persis…
Black holes in dense astrophysical environments, such as globular clusters or in the vicinity of other massive objects, may possess accelerations. Such acceleration would modulate the characteristics of the quasi-periodic oscillations…
In all the microquasars with two hHz QPOs, the ratio of the frequencies is 3:2, supporting our suggestion that a non-linear resonance between two modes of oscillation in the accretion disk plays a role in exciting the observed modulations…
Very low frequency ({\nu} ~ 1.9 mHz) quasi-periodic oscillations (QPO) have been detected in 2 - 60 keV X-rays from 4U1700-37 using auto-correlation function analysis of RXTE archival data. No pulsar signal was detected in the data. Less…
We report the discovery, with NASA's Rossi X-ray Timing Explorer (RXTE), of the first sub-millisecond oscillation found in a celestial X-ray source. The quasi-periodic oscillations (QPO) come from Sco X-1 and have a frequency of…
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…
Although low-frequency quasiperiodic oscillations (LFQPOs) are commonly detected in the X-ray light curves of accreting black hole X-ray binaries, their origin still remains elusive. In this study, we conduct phase-resolved spectroscopy in…
High frequency soft reverberation lags have now been detected from stellar mass and super massive black holes. Their interpretation involves reflection of a hard source of photons onto an accretion disk, producing a delayed reflected…
We have discovered two simultaneous kHz quasi-periodic oscillations (QPOs) in the Z source GX 340+0 with the Rossi X-ray Timing Explorer. The X-ray hardness-intensity and color-color diagram each show a full Z-track, with an extra limb…
We explore the influence of non-geodesic pressure forces that are present in an accretion disk on the frequencies of its axisymmetric and non-axisymmetric epicyclic oscillation modes. {We discuss its implications for models of…
The study of quasi-periodic oscillations in X-ray binaries provides valuable insights into the physics of accretion around compact objects. The M82 galaxy hosts two ultraluminous X-ray sources (ULXs), one of which is suspected to harbor an…
It is well established that timing and spectral properties of Galactic Black Hole (BH) X-ray binaries (XRB) are strongly correlated. In particular, it has been shown that low frequency Quasi-Periodic Oscillation (QPO) frequency - photon…
We studied the frequency and critical mass accretion rate of millihertz quasi-periodic oscillations (mHz QPOs) using a one-zone X-ray burst model. The surface gravity is specified by two kinds of equation of states: neutron star (NS) and…
When thin accretion disks around black holes are perturbed, the main restoring force is gravity. If gas pressure, magnetic stresses, and radiation pressure are neglected, the disk remains thin as long as orbits do not intersect.…
The Seyfert 1 galaxy J1626+5120 is estimated to host a $10^8 M_{\odot}$ black hole (BH) accreting at Eddington ratio $\dot{m}_{\text{Edd}} \approx 0.043$. Its long-term multi-band light curve data show flicker-like variations, but in a…
The study of the quasi-periodic oscillations (QPOs) of X-ray flux observed in the stellar-mass black hole (BH) binaries or quasars can provide a powerful tool for testing the phenomena occurring in strong gravity regime. We thus fit the…
In order to search for the evidence of quasi-periodic oscillation (QPO) in blazar, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For $I$ band on March 19 2010 with low variability…
Using a large quantity of Rossi X-ray Timing Explorer data presented in the literature I offer a detailed investigation into the accuracy of quasiperiodic oscillations (QPO) frequency determination. The QPO phenomenon seen in X-ray binaries…
Kilohertz quasi-periodic oscillations or kHz QPOs occur on the orbital timescale of the inner accretion flow and may carry signatures of the physics of strong gravity (c$^{2}$ ~ GM/R) and possibly clues to constraining the neutron star…
We present an analysis of the high frequency timing properties of the April-May 2000 outburst of the black hole candidate and Galactic microquasar XTE J1550-564, measured with the Rossi X-ray Timing Explorer. The rapid X-ray variability we…
Based on the $Insight$-HXMT archival data, we have detected a new atypical low-frequency quasi-periodic oscillation (LFQPO) in the black hole X-ray binary MAXI J1348$-$630. The new LFQPO is detected in all the three instruments of…