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Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/7270
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dc.contributor.authorVarun-
dc.contributor.authorPradhan, Pragati-
dc.contributor.authorPaul, Biswajit-
dc.contributor.author+2 Co-Authors-
dc.date.accessioned2019-08-13T17:48:15Z-
dc.date.available2019-08-13T17:48:15Z-
dc.date.issued2019-07-20-
dc.identifier.citationAstrophysical Journal, 2019, Vol.880, p61en_US
dc.identifier.issn0004-637X-
dc.identifier.urihttp://hdl.handle.net/2289/7270-
dc.descriptionOpen Accessen_US
dc.description.abstractWe present timing and spectral analysis of data from an observation of the high mass X-ray binary pulsar 4U 1907+09 with the Large Area X-ray Proportional Counter instrument on board AstroSat. The light curve consisted of a flare at the beginning of the observation, followed by persistent emission. The pulsar continues to spin down, and the pulse profile is found to be double-peaked up to 16 keV with the peaks separated by a phase of ~0.45. Significant energy dependence of the pulse profile is seen with diminishing amplitude of the secondary peak above 16 keV, and increasing amplitude of the main peak up to 40 keV with a sharp decline after that. We confirm earlier detection of the cyclotron resonance scattering feature (CRSF) in 4U 1907+09 at ~18.5 ± 0.2 keV in the phase-averaged spectrum with a high detection significance. An intensity resolved spectral analysis of the initial flare in the light curve shows that the CRSF parameters do not change with a change in luminosity by a factor of 2.6. We also performed pulse phase-resolved spectral analysis with 10 independent phase bins. The energy and the strength of the cyclotron line show pulse phase dependence that is in agreement with previous measurements. Two features from the current observation (different energy dependence of the two pulse peaks and a strong CRSF only around the secondary peak) both indicate a deviation from a dipole geometry of the magnetic field of the neutron star, or complex beaming pattern from the two poles.en_US
dc.language.isoenen_US
dc.publisherIOP Sciences for The American Astronomical Societyen_US
dc.relation.urihttps://ui.adsabs.harvard.edu/abs/2019arXiv190602917B/abstracten_US
dc.relation.urihttps://arxiv.org/abs/1906.02917en_US
dc.relation.urihttps://doi.org/10.3847/1538-4357/ab2763en_US
dc.rights2019, The American Astronomical Societyen_US
dc.subjectbinaries: spectroscopicen_US
dc.subjectmethods: data analysisen_US
dc.subjectpulsars: individual (4U 1907+09)en_US
dc.subjectradiation mechanisms: non-thermalen_US
dc.subjectstars: magnetic fielden_US
dc.subjectX-rays: binariesen_US
dc.titlePulse Phase Variation of the Cyclotron Line in HMXB 4U 1907+09 with AstroSat LAXPCen_US
dc.typeArticleen_US
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