Related papers: Time Evolution Of Cyclotron Line of Her X-1; A Det…
The study of variation of measured cyclotron lines is of fundamental importance to understand the physics of the accretion process in magnetized neutron star systems. We investigate the magnetic field formation, evolution and distribution…
We report the timing and spectral studies of the accreting X-ray pulsar 4U 2206+54 using astrosat and hxmt observations taken in 2016 and 2020 respectively. X-ray pulsations from the system are detected by both missions. The astrosat…
After nearly a decade of quiescence, the transient Be/X-ray binary pulsar RX J0520.5-6932 underwent an outburst in 2024. We performed X-ray monitoring of the source with NICER and AstroSat near the peak of the event. Our primary objective…
We investigate time variations and detailed spatial structures of X-ray synchrotron emission in the northeastern limb of SN 1006, using two Chandra observations taken in 2000 and 2008. We extract spectra from a number of small (about 10")…
We report on our analysis of a large sample of energy dependent pulse profiles of the X-ray binary pulsar Hercules X-1. We find that all data are compatible with the assumption of a slightly distorted magnetic dipole field as sole cause of…
Results of a BeppoSAX observation of Her X-1 in 2000 October during the first main-on state after the longest recorded anomalous low-state are presented. The 0.1-30 keV spectrum, light curve and pulse profile are all consistent with those…
X-ray spectra of the isolated neutron star RBS1223 obtained with the instruments on board XMM-Newton in December 2001 and January 2003 show deviations from a Planckian energy distribution at energies below 500 eV. The spectra are well fit…
We report on the temporal properties of the ULX pulsar M51 ULX-7 inferred from the analysis of the 2018-2020 Swift/XRT monitoring data and archival Chandra data obtained over a period of 33 days in 2012. We find an extended low flux state,…
We report on \textit{NuSTAR} observations of the well-known wind-accreting X-ray pulsar \source\ during a strong spin-up episode that took place in January-March 2019. A high luminosity of the source in a most recent observation allowed us…
We report observations of SMC X-1 in three new high-intensity states with ROSAT HRI in December 1995, May 1997, and March 1998 in which pulsations with a period of 0.70769+/-0.00006 sec, 0.70706+/-0.00001 sec, and 0.706707+/-0.00001 sec…
The wind-accreting X-ray binary pulsar and cyclotron line source Vela X-1 has been observed extensively during INTEGRAL Core Program observations of the Vela region in June-July and November-December 2003. In the latter set of observations…
We have observed variations in the optical emission lines from the X-ray binary Circinus X-1. These variations may be attributed both to orbital variations and to long term secular changes in line strength. We have detected double-peaked…
We present a detailed spectro-temporal study of the Be X-ray binary pulsar $1A$ $1118-61$ during its brightest recorded outburst in 2026, using \textit{Swift} and \textit{NuSTAR} observations, and compare its properties with the 2009…
We present here the preliminary results of the study of the fluorescent iron line emission from X-ray pulsars with Be companions. We propose to use properties of this emission to investigate the spatial distribution and physical conditions…
Multi-wavelength monitoring of Mrk 335 with Swift between 2007-2019 are used to construct annual spectral energy distributions and track year-to-year changes. Non-contemporaneous archival data prior to 2007 are used to build a bright state…
The spectrum of cyclotron radiation produced by electrons with a strongly anisotropic velocity distribution is calculated taking into account higher harmonics. The motion of the electrons is assumed to be ultrarelativistic along the…
Pulsations from the high mass X-ray binary AXJ1910.7+0917 were discovered during Chandra observations performed in 2011 (Israel et al. 2016). We report here more details on this discovery and discuss the source nature. The period of the…
We analyze all X-ray timing data on 1E 1207.4-5209 in supernova remnant PKS 1209-51/52 gathered in 2000-2005, and find a highly stable rotation with P=424.130451(4) ms and period derivative of (9.6 +/- 9.4)E-17 s/s. This refutes previous…
NGC300 ULX1 is an ultra-luminous X-ray pulsar, showing an unprecedented spin evolution, from about 126 s to less than 20 s in only 4 years, consistent with steady mass accretion rate. Following its discovery we have been monitoring the…
This paper presents a detailed analysis of the temporal and spectral variability of the low-energy peaked BL Lac object S5 0716+714 with a long (~74 ks)X-ray observation performed by XMM-Newton on 2007 September 24-25. The source…