Gaurava K. Jaisawal

TIMING AND SPECTRAL PROPERTIES OF Be/X-RAY PULSAR EXO 2030+375 DURING A TYPE I OUTBURST

We present results from a study of broadband timing and spectral properties of EXO 2030+375 using a Suzaku observation. Pulsations with a period of 41.41?s and strong energy-dependent pulse profiles were clearly detected up to 100?keV. Narrow dips are seen in the profiles up to ~70?keV. The presence of prominent dips at several phases in the profiles up to such high energy ranges was not seen before. At higher energies, these dips gradually disappeared and the profile appeared to be single-peaked. The 1.0-200.0?keV broadband spectrum is found to be well described by a partial covering high-energy cutoff power-law model. Several low-energy emission lines are also detected in the pulsar spectrum. We fitted the spectrum using neutral as well as partially ionized absorbers along with the above continuum model yielding similar parameter values. The partial covering with a partially ionized absorber resulted in a marginally better fit. The spectral fitting did not require any cyclotron feature in the best-fit model. To investigate the changes in spectral parameters at dips, we carried out pulse-phase-resolved spectroscopy. During the dips, the value of the additional column density was estimated to be high compared to other pulse phases. While using a partially ionized absorber, the value of the ionization parameter is also higher at the dips. This may be the reason for the presence of dips up to higher energies. No other spectral parameters show any systematic variation with pulse phases of the pulsar.

Suzaku view of the Be/X-ray binary pulsar GX 304-1 during Type I X-ray outbursts

We report the timing and spectral properties of Be/X-ray binary pulsar GX 304-1 by using two Suzaku observations during its 2010 August and 2012 January X-ray outbursts. Pulsations at ~275 s were clearly detected in the light curves from both the observations. Pulse profiles were found to be strongly energy-dependent. During 2010 observation, prominent dips seen in soft X-ray (

Detection of cyclotron resonance scattering feature in high-mass X-ray binary pulsar SMC X-2

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Detection of fundamental and first harmonic cyclotron line in X-ray pulsar Cep X-4

10 keV) pulse profiles were found to be absent at higher energies. However, during 2012 observation, the pulse profiles were complex due to the presence of several dips. Significant changes in the shape of the pulse profiles were detected at high energies (

A Suzaku View of Accretion-powered X-Ray Pulsar GX 1+4

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Suzaku observation of Be/X-ray binary pulsar EXO 2030＋375

35 keV). A phase shift of

Decade long RXTE monitoring observations of Be/X-ray binary pulsar EXO 2030+375

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Broad-band spectroscopy of the eclipsing high-mass X-ray binary 4U 1700−37 with Suzaku

0.3 was detected while comparing the phase of main dip in pulse profiles below and above

Understanding the spectral and timing behaviour of a newly discovered transient X-ray pulsar Swift J0243.6+6124

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Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component

35 keV. Broad-band energy spectrum of pulsar was well described by a partially absorbed Negative and Positive power-law with Exponential cutoff (NPEX) model with 6.4 keV iron line and a cyclotron absorption feature. Energy of cyclotron absorption line was found to be