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dc.contributor.authorInam, Sitki Cagdas
dc.date.accessioned2022-06-21T07:33:02Z
dc.date.available2022-06-21T07:33:02Z
dc.date.issued2021
dc.identifier.issn0035-8711en_US
dc.identifier.urihttps://watermark.silverchair.com/stab3547.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAtkwggLVBgkqhkiG9w0BBwagggLGMIICwgIBADCCArsGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMHPEy_yUIN94PtQmNAgEQgIICjEkukT3THhkiWQQKLSzSumvlzlHRNHaqcsVhjGAL0MzPnQSMGOYgVNZZ1gE9NxnycWbbbNq2gJuPlKF7_kcnsH7HCD8SIDtmi1TQL_EVCeIlcOEQus6Rx4ONztwGQXUn4C5FmJ4wD7PBqcRdx0haiTE-uogzV56UnxL_1zfY_gdEWzuApGv_0EFA8Y8tW51yZL_kLLSTScuQ5tZw13bSQMHwp7Nt77qVXJHQR7HgAatGF3n_k4eLD5o2M0Ebnyc6FdaObPemR3gFl7Ypx0gb8SkSZWxCBdwAkwXSFu_0Ih9Y_8sCF85WfGlmQ3RxkGTe7SkuF6tzT0a4TG-5FM4zRMjnma7AKVARKyOS_-5AKYVhK-CsSNWQPjBPLez6fCJcaJ9BKT56mlsEeVjHyfYocZZbjU9z_9KEmejfUvxz3kl7JvtC3zFM89ezoRxiDJlFYMlSV38RPDh2Y_qhKYAzFHHukyL8Mz1Xc7mImjXaFdAYHeJ2O4f3fPlyeMvkfv-_6JlISDeNdW2cU0DV0l9caX2ibcPwu7I3xBjiJHBCaRzZKgpDQPekRuVmCO6nDfU6livETGsB6b9se4hgjRgtLJOuwf9EIaPnpr-RdiFFIplQrBG2dABp_hMNdQnkQns7wmI9sR-55FYFmK0NE6UEGe-L4RFejbyeONWqAwcM2zoUZrDbsUaoRbF2YIUJFFfAGuVrdSkwgrTVpVIc55GXGTefoTNQYanTU9mGwsmz3V92Fd7oL7Tgu9fTTF6QhrH8u60Blb0f0PBmduLyrKwxHcuboL-rw7yJzX2qybennP46XLvtCkuGosEDsFIm833n7SSRPvGI7yYbozfIcMhOcYvEdBh5STglCr_QodU
dc.identifier.urihttp://hdl.handle.net/11727/7072
dc.description.abstractWe investigate timing and spectral characteristics of the transient X-ray pulsar 2S 1417-624 during its 2018 outburst with NICER follow up observations. We describe the spectra with high-energy cut-off and partial covering fraction absorption (PCFA) model and present flux-dependent spectral changes of the source during the 2018 outburst. Utilizing the correlation-mode switching of the spectral model parameters, we confirm the previously reported sub-critical to critical regime transitions and we argue that secondary transition from the gas-dominated to the radiation pressure-dominated disc do not lead us to significant spectral changes below 12 keV. Using the existing accretion theories, we model the spin frequency evolution of 2S 1417-624 and investigate the noise processes of a transient X-ray pulsar for the first time using both polynomial and luminosity-dependent models for the spin frequency evolution. For the first model, the power density spectrum of the torque fluctuations indicate that the source exhibits red noise component (Gamma similar to -2) within the time-scales of outburst duration which is typical for disc-fed systems. On the other hand, the noise spectrum tends to be white on longer time-scales with high timing noise level that indicates an ongoing accretion process in between outburst episodes. For the second model, most of the red noise component is eliminated and the noise spectrum is found to be consistent with a white noise structure observed in wind-fed systems.en_US
dc.language.isoengen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectaccretionen_US
dc.subjectaccretion discsen_US
dc.subjectstars: neutronen_US
dc.subjectpulsars: individual: 2S 1417-624en_US
dc.titleTiming and spectral analysis of 2S 1417-624 during its 2018 outbursten_US
dc.typearticleen_US
dc.relation.journalMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETYen_US
dc.contributor.departmentBaşkent Üniversitesien_US
dc.identifier.volume510en_US
dc.identifier.issue1en_US
dc.identifier.startpage1438en_US
dc.identifier.endpage1449en_US
dc.identifier.wos000745080400042en_US
dc.identifier.scopus2-s2.0-85126678216en_US
dc.contributor.orcID0000-0003-0820-9186en_US
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergien_US


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