scholarly journals Evolution of timing and spectral characteristics of 4U 1901+03 during its 2019 outburst using the Swift and NuSTAR observatories

2020 ◽  
Vol 500 (1) ◽  
pp. 1350-1365
Author(s):  
Aru Beri ◽  
Tinku Girdhar ◽  
Nirmal K Iyer ◽  
Chandreyee Maitra
Keyword(s):  
Energy Band ◽  
Cyclotron Resonance ◽  
Abrupt Change ◽  
Spectral Characteristics ◽  
Resonance Scattering ◽  
Absorption Feature ◽  
Phase Dependence ◽  
X Ray ◽  
Pulse Phase ◽  
Broadband Spectroscopy

ABSTRACT We report the results from a detailed timing and spectral study of a transient X-ray pulsar, 4U 1901+03 during its 2019 outburst. We performed broadband spectroscopy in the 1–70 $\rm keV$ energy band using four observations made with Swift and NuSTAR at different intensity levels. Our timing results reveal the presence of highly variable pulse profiles dependent on both luminosity and energy. Our spectroscopy results showed the presence of a cyclotron resonance scattering feature (CRSF) at ∼ 30 keV. This feature at 30 keV is highly luminosity and pulse phase dependent. Phase-averaged spectra during the last two observations, made close to the declining phase of the outburst, showed the presence of this feature at around $30~\rm {keV}$. The existence of CRSF at 30 keV during these observations is well supported by an abrupt change in the shape of pulse profiles found close to this energy. We also found that 30 keV feature was significantly detected in the pulse phase-resolved spectra of observations made at relatively high luminosities. Moreover, all spectral fit parameters showed a strong pulse phase dependence. In line with the previous findings, an absorption feature at around $10~\rm {keV}$ is significantly observed in the phase-averaged X-ray spectra of all observations and also showed a strong pulse phase dependence.

Discovery of a Cyclotron Resonance Scattering Feature in the X-Ray Spectrum of XTE J1946+274

2001 ◽  
Vol 563 (1) ◽  
pp. L35-L39 ◽  
Author(s):  
W. A. Heindl ◽  
W. Coburn ◽  
D. E. Gruber ◽  
R. E. Rothschild ◽  
I. Kreykenbohm ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Resonance Scattering ◽  
X Ray

scholarly journals Discovery of a Third Harmonic Cyclotron Resonance Scattering Feature in the X-Ray Spectrum of 4U 0115+63

1999 ◽  
Vol 521 (1) ◽  
pp. L49-L53 ◽  
Author(s):  
W. A. Heindl ◽  
W. Coburn ◽  
D. E. Gruber ◽  
M. R. Pelling ◽  
R. E. Rothschild ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Resonance Scattering ◽  
Third Harmonic ◽  
X Ray

scholarly journals Study of recent outburst in the Be/X-ray binary RX J0209.6−7427 with AstroSat: a new ultraluminous X-ray pulsar in the Magellanic Bridge?

2020 ◽  
Vol 495 (3) ◽  
pp. 2664-2672 ◽  
Author(s):  
Amar Deo Chandra ◽  
Jayashree Roy ◽  
P C Agrawal ◽  
Manojendu Choudhury
Keyword(s):  
Energy Band ◽  
Spectral Characteristics ◽  
Spectral Studies ◽  
X Rays ◽  
Energy Bands ◽  
Large Area ◽  
Pulse Profile ◽  
X Ray ◽  
Outburst Energy ◽  
Area X

ABSTRACT We present the timing and spectral studies of RX J0209.6–7427 during its rare 2019 outburst using observations with the Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counter (LAXPC) instruments on the AstroSat satellite. Pulsations having a periodicity of 9.29 s were detected for the first time by the NICER mission in the 0.2–10 keV energy band and, as reported here, by AstroSat over a broad energy band covering 0.3–80 keV. The pulsar exhibits a rapid spin-up during the outburst. Energy resolved folded pulse profiles are generated in several energy bands in 3–80 keV. To the best of our knowledge this is the first report of the timing and spectral characteristics of this Be binary pulsar in hard X-rays. There is suggestion of evolution of the pulse profile with energy. The energy spectrum of the pulsar is determined and from the best-fitting spectral values, the X-ray luminosity of RX J0209.6−7427 is inferred to be 1.6 × 1039 erg s−1. Our timing and spectral studies suggest that this source has features of an ultraluminous X-ray pulsar in the Magellanic Bridge. Details of the results are presented and discussed in terms of the current ideas.

X-ray spectra of Hercules X-1. III - Pulse phase dependence in the high-energy continuum

1978 ◽  
Vol 225 ◽  
pp. 988 ◽  
Author(s):  
S. H. Pravdo ◽  
R. W. Bussard ◽  
R. H. Becker ◽  
E. A. Boldt ◽  
S. S. Holt ◽  
...  
Keyword(s):  
High Energy ◽  
Phase Dependence ◽  
X Ray ◽  
Pulse Phase

scholarly journals Pulse-phase dependence of emission lines in the X-ray pulsar 4U 1626–67

2015 ◽  
Vol 451 (1) ◽  
pp. 508-516 ◽  
Author(s):  
Aru Beri ◽  
Biswajit Paul ◽  
Gulab C. Dewangan
Keyword(s):  
Emission Lines ◽  
Phase Dependence ◽  
X Ray ◽  
Pulse Phase

scholarly journals Revisiting BeppoSAX and NuSTAR observations of KS 1947+300 and the missing cyclotron line

2020 ◽  
Vol 493 (3) ◽  
pp. 3442-3448
Author(s):  
R Doroshenko ◽  
S Piraino ◽  
V Doroshenko ◽  
A Santangelo
Keyword(s):  
Cyclotron Resonance ◽  
Broad Band ◽  
Resonance Scattering ◽  
Continuum Models ◽  
Line Detection ◽  
Soft Component ◽  
Additional Absorption ◽  
X Ray ◽  
Two Component ◽  
Cyclotron Line

ABSTRACT Motivated by the alleged detection of a cyclotron resonance scattering feature in the X-ray spectrum of the Be-transient KS 1947+300 with NuSTAR, not observed with other observatories, we have revisited the available observations of the source to clarify the origin of the reported feature. We focus on the analysis of observations obtained with the BeppoSAX observatory during the 2001 outburst, and by NuSTAR in 2013, when the discovery of the line was reported. We find that in both cases, the source broad-band X-ray continuum can be well described with a two-component Comptonization model, which does not require an additional absorption-like feature. In addition, we show that low-significance residuals mimicking the line, which appear using different continuum models, are consistent with known calibration uncertainties. We therefore conclude that the reported cyclotron line detection is largely questionable, and thus the question on the strength of the source magnetic field remains open. We briefly discuss the origin of the observed broad-band continuum in the context of the pulse-phase-resolved analysis conducted for BeppoSAX data and speculate that the soft component may be associated with the emission from polar areas of the pulsar irradiated by the accretion column.

scholarly journals POSSIBLE DETECTION OF A CYCLOTRON RESONANCE SCATTERING FEATURE IN THE X-RAY PULSAR 4U 1909+07

2013 ◽  
Vol 779 (1) ◽  
pp. 54 ◽  
Author(s):  
Gaurava K. Jaisawal ◽  
Sachindra Naik ◽  
Biswajit Paul
Keyword(s):  
Cyclotron Resonance ◽  
Resonance Scattering ◽  
X Ray

scholarly journals The Cyclotron Resonance Scattering Features In Neutron Star Binaries Observed By INTEGRAL

2012 ◽  
Vol 8 (S290) ◽  
pp. 333-334
Author(s):  
Wei Wang
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Cyclotron Resonance ◽  
Gamma Ray ◽  
Physical Mechanism ◽  
Angular Resolution ◽  
High Sensitivity ◽  
Resonance Scattering ◽  
X Ray ◽  
Accretion Physics

AbstractCyclotron resonance scattering features (CRSF) are the direct observational evidence for the strongly magnetized neutron stars. Since the first detection of the absorption line in the X-ray source Her X-1 thirty years ago, more than ten sources are indentified as the strongly magnetized neutron stars through detecting CRSFs. INTEGRAL is the new X-ray/gamma-ray mission with good angular resolution, high sensitivity and spectral resolution in the range of 18 C 200 keV, so that it provides us a good chance to detect the CRSFs in neutron star systems. INTEGRAL has confirmed the line features in 5 previous known sources and discovered 4 new candidates. Physical mechanism of CRSFs and accretion physics can be probed with detailed spectral analysis.

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