Related papers: X-ray variability of transitional millisecond puls…
We investigate the photometric variability of magnetized stars, particularly neutron stars, accreting through a magnetic Rayleigh-Taylor-type instability at the disk-magnetosphere interface, and compare it with the variability during stable…
The properties of accretion disks around stars and brown dwarfs in the SOri cluster (age 3 Myr) are studied based on NIR time series photometry supported by MIR spectral energy distributions. We monitor ~30 young low-mass sources over 8…
Transitional millisecond pulsars are millisecond pulsars that switch between a rotation-powered millisecond pulsar state and an accretion-powered X-ray binary state, and are thought to be an evolutionary stage between neutron star low-mass…
Using the Rossi X-ray Timing Explorer (RossiXTE), astronomers have discovered that disk-accreting neutron stars with weak magnetic fields produce three distinct types of high-frequency X-ray oscillations. These oscillations are powered by…
The discovery of source states in the X-ray emission of black-hole binaries and neutron-star low-mass X-ray binaries constituted a major step forward in the understanding of the physics of accretion onto compact objects. While there are…
This paper presents an investigation of spectral properties of 10 millisecond pulsars (MSPs) discovered by the uGMRT, observed from 2017-2023 using band 3 (300-500 MHz) and 4 (550-750 MHz) of uGMRT. For these MSPs, we have reported a range…
In this paper, we report on the analysis of the peculiar X-ray variability displayed by the accreting millisecond X-ray pulsar IGR J00291+5934 in a 80 ks-long joint NuSTAR and XMM-Newton observation performed during the source outburst in…
Millisecond X-ray pulsars consist of a rapidly-spinning neutron star accreting from a low-mass stellar companion, and are the long-sought evolutionary progenitors of millisecond radio pulsars, as well as promising candidate sources for…
The accreting millisecond pulsar XTE J1814-338 exhibits oscillations at the known spin frequency during Type I X-ray bursts. The properties of the burst oscillations reflect the nature of the thermal asymmetry on the stellar surface. We…
The inner regions of accretion disks of weakly magnetized neutron stars are affected by general relativity and stellar magnetic fields. Even for field strengths sufficiently small so that there is no well-defined magnetosphere surrounding…
(Abridged) Recent XMM-Newton studies of X-ray variability in the hard states of black hole X-ray binaries (BHXRBs) imply that the variability is generated in the 'standard' optically-thick accretion disc. The variability originates in the…
The precise origins of the millisecond radio pulsars, discovered in the early 1980s, remain uncertain until this day. They plausibly evolve from accreting low magnetic-field neutron stars in X-ray binary systems. If so, these stars should…
The properties of the aperiodic variability in X-ray binaries with black holes are considered. The power spectra of the luminosity variability for a flat accretion disk that is an emission source with a power-law energy spectrum have been…
Previously, observations with the Rossi X-ray Timing Explorer showed that millisecond oscillations occur preferentially in thermonuclear X-ray bursts with photospheric radius expansion from sources rotating near 600 Hz, while they occur…
Transitional millisecond pulsars are accreting millisecond pulsars that switch between accreting X-ray binary and millisecond radio pulsar states. Only a handful of these objects have been identified so far. Terzan 5 CX1 is a variable hard…
We have detected quasi-periodic oscillations (QPOs) near 1 kHz from the low mass X-ray binary 4U 0614+091 in observations with XTE. The observations span several months and sample the source over a large range of X-ray luminosity. In every…
In addition to coherent pulsation, many accreting neutron stars exhibit flaring activity and strong aperiodic variability on time scales similar to or shorter than their pulsation period. Such a behavior shows that the accretion flow in the…
We calculate upper bounds on the inner radii of geometrically thin accretion disks in galactic black-hole systems by relating their rapid variability properties to those of neutron stars. We infer that the inner disk radii do not exhibit…
AGN, powered by accretion onto SMBHs, are thought to be scaled up versions of Galactic black hole X-ray binaries (BH-XRBs). In the past few years evidence of such correspondence include similarities in the broadband shape of the X-ray…
We present the results of our extensive binary orbital motion corrected pulsation search for 13 low mass X-ray binaries (LMXBs). These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1122 Hz, and…