Related papers: Quasi-Periodic X-ray Oscillations in the Source Sc…
Using large number of Rossi X-ray Time Explorer observations of Sco X-1 we present a detailed investigation of the transition layer (TL) and the relativistic precession (RP) models. These models predict the existence of the invariant…
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 analyze all available RXTE data on a sample of 13 low mass X-ray binaries with known neutron star spin that are not persistent pulsars. We carefully measure the correlations between the centroid frequencies of the quasi-periodic…
We investigate the kilohertz quasi-periodic oscillations of low-mass X-ray binaries within the Hartle-Thorne spacetime. On the basis the relativistic precession model we extract the total mass $M$, angular momentum $J$, and quadrupole…
The Neutron Star X-ray binary Sco X-1 is one of the brightest Z-type sources in our Galaxy, showing frequent periods of flaring activity and different types of relativistic outflows. Observations with RXTE have shown that the strongest…
Recently discovered quasi periodic oscillations in the X-ray brightness of low mass X-ray binaries are used to derive constraints on the mass of the neutron star component and the equation of state of neutron star matter. The observations…
Recent discovery of kilohertz quasi-periodic brightness oscillations of low mass X-ray binaries (LMXBs) has attracted attention to highly relativistic periodic motion near accreting neutron stars. Most models proposed so far involve…
Highlights from the RXTE All Sky Monitor (ASM) during 1996 and 1997 are reviewed with particular attention to X-ray transients. The ASM has detected 117 sources. These include 12 recurrent transients and 10 new X-ray sources, some of which…
Before the launch of the Rossi X-ray Timing Explorer (RXTE) it was recognized that neutron star accretion disks could extend inward to very near the neutron star surface, and thus be governed by millisecond timescales. Previous missions…
The luminous X-ray binary and black-hole candidate LMC X-1 has been observed with the Rossi X-ray Timing Explorer (RXTE) to search for quasi-periodic oscillations (QPO), previously reported in its high state. The source was observed monthly…
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…
In light of the relativistic precession model, we present here detailed analyses, extending the ones performed in the Schwarzschild and Kerr spacetimes. We consider the kilohertz quasi-periodic oscillations in the Hartle-Thorne spacetime,…
Recent observations by XMM-Newton detected rotational pulsations in the total brightness and spectrum of several neutron stars. To properly interpret the data, accurate modeling of neutron star emission is necessary. Detailed analysis of…
We have investigated the variability of the binary X-ray pulsar, SMC X-1, in data from several X-ray observatories. We confirm the ~60-day cyclic variation of the X-ray flux in the long-term monitoring data from the RXTE and CGRO…
The high frequency quasiperiodic oscillations (QPOs) in the X-ray spectra of the millisecond pulsar XTE J1807-294 are under consideration. By application of the relativistic precession (RP) model an attempt is made to approximate the…
The Rossi X-Ray Timing Explorer (RXTE) has found that the neutron stars in low-mass X-ray binaries exhibit oscillations in the range 300-1200 Hz. Persistent emission may exhibit one or both of two features. In bursts a nearly coherent…
Black hole and neutron star X-ray binary systems routinely show quasi-periodic oscillations (QPOs) in their X-ray flux. Despite being strong, easily measurable signals, their physical origin has long remained elusive. However, recent…
We present a comprehensive classification of all observed QPOs within the framework of the transition layer model using a large set of Rossi X-ray Timing Explorer (RXTE) data for Sco X-1. The model assumes an optically thin material along…
Quasi-periodic oscillation (QPOs) analysis is important for understanding the dynamical behavior of many astrophysical objects during transient events such as gamma-ray bursts, solar flares, magnetar flares, and fast radio bursts. In this…
Boutloukos et al. (2006) discovered twin-peak quasi-periodic oscillations (QPOs) in 11 observations of the peculiar Z-source Circinus X-1. Among several other conjunctions the authors briefly discussed the related estimate of the compact…