Related papers: A phase-resolved spectroscopic study of the X-ray …
We report on the first XMM-Newton observation of the Anomalous X-ray Pulsar 1RXS J170849.0-400910. The source was observed in 2003 August and was found at a flux level a factor of about two lower than previous observations. Moreover, a…
We report the results of temporal and spectral analysis performed on the X-ray pulsar 4U 1538-52 observed by BeppoSAX. We obtained a new estimate of the spin period of the neutron star P=528.24 \pm 0.01 s (corrected for the orbital motion…
X-ray spectra of many accreting pulsars exhibit significant variations as a function of flux and thus of mass accretion rate. In some of these pulsars, the centroid energy of the cyclotron line(s), which characterizes the magnetic field…
In this study, we examine 51 archival NICER observations and 6 archival NuSTAR observations of the neutron star (NS) ultra-compact X-ray binary (UCXB) 4U 0614+091, which span over 5 years. The source displays persistent reflection features,…
We have studied the timing and spectral properties of the BeXB 4U 1901+03 during the 2019 outburst using \textit{NuSTAR}, \textit{Swift}, and \textit{NICER} observations. Flares are in all observations and were of tens to hundreds of…
The Be/X-ray binary pulsar RX J0440.9+4431 underwent a giant outburst in late 2022 and lasted three months. The Insight-HXMT has observed this source at several instances of the entire outburst in 2022-2023. We used these bright outburst…
We investigate the X-ray variability of the supergiant X-ray binary 4U 1907+09 using the new NuSTAR observation of 2024. The source had a relatively stable flux level during previous NuSTAR observations, but the flux varied significantly…
We present an analysis of all SAX observations of NGC 4151. This source was observed 5 times from 1996 to 2001 with durations ranging from a day to four days. The intrinsic continuum, is absorbed at low energies by a complex system: a cold…
In November 2020, A0535+26 underwent one of its brightest outbursts, reaching nearly 12 Crab in X-ray flux. Observed by \textit{Insight-HXMT}, \textit{NuSTAR}, \textit{NICER}, and \textit{AstroSat}, this event provided valuable insights…
We present a detailed analysis of observations of the high mass X-ray binary Cen X-3 spanning two consecutive binary orbits performed with the RXTE satellite in early March 1997. The PCA and HEXTE light curves both show a clear reduction in…
We present two observations of the high-mass X-ray binary GX 301-2 with NuSTAR, taken at different orbital phases and different luminosities. We find that the continuum is well described by typical phenomenological models, like a very…
Cyclotron resonance scattering features are observed in the spectra of some X-ray pulsars and show significant changes in the line energy with the pulsar luminosity. In a case of bright sources, the line centroid energy is anti-correlated…
Isolated neutron stars are higly magnetized, fast rotating end points of stellar evolution. They are now becoming directly observable through X-ray astronomy, owing to their high surface temperatures. In particular, features in their X-ray…
4U1812-12 is a faint persistent and weakly variable neutron star X-ray binary. It was observed by BeppoSAX between April 20th and 21st, 2000 in a hard spectral state with a bolometric luminosity of ~2x10^36 ergs/s. Its broad band energy…
The 8.7s X-ray pulsar 4U 0142+61 was monitored by BeppoSAX between January 1997 and February 1998. This source belongs to the rapidly growing class of "anomalous" X-ray pulsars (AXPs) which have pulse periods in the 6-12s range and no…
The azimuthal angle dependence observed in the resonant X-ray scattering in phase IV of Ce$_{0.7}$La$_{0.3}$B$_6$ is analyzed theoretically. It is shown that the peculiar angle dependence observed in the E2 channel is consistent with the…
The results of the broadband spectral and timing study of the transient X-ray pulsar GRO J2058+42 in a wide energy range at a low luminosity $L_{x} \simeq 2.5\times 10^{36}$ erg s$^{-1}$ are reported. The data revealed that the pulse…
Cyclotron resonance scattering features observed in the spectra of some X-ray pulsars show significant changes of the line energy with the pulsar luminosity. At high luminosities, these variations are often associated with the onset and…
We present an analysis of the 2-150 keV spectrum of the transient X-ray pulsar V0332+53 taken with the Rossi X-Ray Timing Explorer (RXTE) in 2004 December. We report on the detection of three cyclotron resonance features at 27, 51, and 74…
The blazar 1ES 1959+650 was observed twice by BeppoSAX in September 2001 simultaneously with optical observations. We report here the X-ray data together with the optical, R_C magnitude, light curve since August 1995. The BeppoSAX…