Related papers: The variable cyclotron line in GX 301-2

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…

We present pulse phase averaged spectra of the high mass X-ray binary pulsar 4U 1538-52/QV Nor. Observations of this persistent accreting pulsar were made with the Rossi X-ray Timing Explorer (RXTE). We study the variability of cyclotron…

We present pulse phase-resolved X-ray spectra of the high mass X-ray binary Vela X-1 using the Rossi X-ray Timing Explorer. We observed Vela X-1 in 1998 and 2000 with a total observation time of ~90 ksec. We find an absorption feature at…

Context. The High-Mass X-ray Binary (HMXB) system GX 301$-$2 is a persistent source with a well-known variable cyclotron line centered at 35 keV. Recently, a second cyclotron line at 50 keV has been reported with a presumably different…

We investigate the cyclotron resonant scattering features (CRSFs) of the accreting X-ray pulsar Cen X-3 and significantly detect the 29 keV cyclotron line features in the hard X-ray averaged spectroscopy studies based on the recent…

We report the discovery of a cyclotron resonance scattering feature (CRSF) in the X-ray spectrum of GX 304-1, obtained by RXTE and Suzaku during major outbursts detected by MAXI in 2010. The peak intensity in August reached 600 mCrab in the…

Observed cyclotron resonant scattering features (CRSFs) in X-ray pulsars (XRPs) exhibit strong variability. In the subcritical luminosity regime, the centroid energy ($E_{CRSF}$) and line width ($\sigma_{CRSF}$) often show positive…

Her X-1 is one of the the most intensively studied Accreting X-ray Binary Pulsars (AXBPs). This is largely because it is a bright and persistent X-ray pulsar, showing the largest variety of observable phenomena, partly due to the favorable…

We present the analysis of RXTE monitoring data obtained during the January 2009 outburst of the hard X-ray transient 1A 1118-61. Using these observations the broadband (3.5-120 keV) spectrum of the source was measured for the first time…

We present a detailed study of the high mass X-ray binary Vela X-1, using observations performed by Insight-HXMT in 2019 and 2020, concentrating on timing analysis and spectral studies including pulse phase-resolved spectroscopy. The…

Cyclotron resonant scattering features (CRSFs) are the absorption features in the X-ray spectra of strongly magnetized accretion neutron stars (NSs), which are probably the most reliable probe to the surface magnetic fields of NSs. The high…

Context. Cyclotron resonant scattering features (CRSFs) in accreting X-ray pulsars are often difficult to detect, especially when shallow or variable. Recent studies have shown that combining spectral and timing analyses enhances their…

We report the first report on cyclotron line studies with the LAXPC instrument onboard AstroSat of the High mass X-ray Binary pulsar 4U 1538-52. During the observation of source which spanned about one day with a net exposure of 50 ks,the…

X 1822-371 is an eclipsing binary system with a period close to 5.57 hr and an orbital period derivative $\dot{P}_{\rm orb}$ of 1.42(3)$\times 10^{-10}$ s s$^{-1}$. The extremely high value of its $\dot{P}_{\rm orb}$ is compatible with a…

We study the behaviour of the cyclotron resonant scattering feature (CRSF) of the high mass X-ray binary Vela X-1 using the long-term hard X-ray monitoring performed by the Burst Alert Telescope (BAT) on board Swift. High statistics,…

We have performed pulse phase resolved spectroscopy of the Cyclotron Resonance Scattering Features (CRSF) of some bright accretion powered X-ray pulsars like 1A 1118-61, Vela X-1, A0535+26, XTE J1946+274, 4U 1907+09, 4U 1626-67 and GX 301-2…

We have monitored a Type II outburst of the Be/X-ray binary MXB 0656-072 in a series of pointed RXTE observations during October through December 2003. The source spectrum shows a cyclotron resonance scattering feature at 32.8 +/- 0.5 keV,…

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…

We report the orbital X-ray variability of high mass X-ray binary (HMXB) GX301--2. GX301--2 undergone a spin up process in 2018--2020 with the period evolving from $\sim$ 685 s to 670 s. The energy resolved pulse-profiles of the pulsar in…

We present the results of the neutron star X-ray binary system Cen X-3 performed by $Insight$-HXMT with two observations during 2017 and 2018. During these two observations, the source reached a X-ray luminosity of $\sim 10^{38}$ erg…