Yazar "Erkut, Mehmet Hakan" seçeneğine göre listele

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    On the Mass and Magnetic Field of the Neutron Star in the Ultraluminous X-Ray Source NGC 300 ULX1
    (2021) Erkut, Mehmet Hakan
    The accreting compact objects in most of ultraluminous X-ray sources (ULXs) are likely to be neutron stars rather than black holes as suggested by the recent detection of periodic pulsations from some of these sources located in neighboring galaxies and one ULX that has hitherto been discovered in our own galaxy. As a member of the ULX family, NGC 300 ULX1 is a new pulsating ULX (PULX) spinning up at substantially high rates compared with other PULXs. In this paper, the strength of the magnetic field on the surface of the neutron star is inferred from the energy of the cyclotron absorption line detected in the pulsed X-ray spectrum of NGC 300 ULX1 and the plausible ranges for the neutron-star mass and beaming fraction are estimated using the observed spin period and period derivative of the pulsar and the measured X-ray flux of the source. Our analysis favors proton cyclotron resonance scattering as a viable mechanism to account for both the observed cyclotron energy and high spin-up rates provided that the absorption line is generated close to the surface of the neutron star.
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    On the spin period of the neutron star in the ultraluminous X-ray source M51 ULX-8
    (Avrupa Bilim ve Teknoloji Dergisi, 2021-08) Erkut, Mehmet Hakan
    ABSTRACT: The recent discovery of periodic pulsations from several members of the ultraluminous X-ray source (ULX) family in nearby galaxies as well as in our own galaxy unveiled the nature of the accreting compact object. Neutron stars rather than black holes are currently believed to power a substantial number of ULXs whether or not pulsations are observed. The detection of cyclotron absorption lines in the X-ray spectrum of a ULX provides an alternative way to identify the compact object as a neutron star. Among the non-pulsating ULXs, the presence of a cyclotron resonance scattering feature (CRSF) in the spectrum of M51 ULX-8 has been reported. In the present work, the magnetic field strength on the surface of the neutron star in M51 ULX-8 is inferred from the energy of the observed CRSF to estimate the beaming fraction in X-ray emission and more importantly the observable range for the elusive neutron-star spin period to be hopefully discovered by the forthcoming space missions in the near future.
  • Küçük Resim Yok
    Öğe
    On the Spin Period of the Neutron Star in the Ultraluminous X-RaySource M51 ULX-8
    (2021) Erkut, Mehmet Hakan
    The recent discovery of periodic pulsations from several members of the ultraluminous X-ray source (ULX) family in nearby galaxiesas well as in our own galaxy unveiled the nature of the accreting compact object. Neutron stars rather than black holes are currentlybelieved to power a substantial number of ULXs whether or not pulsations are observed. The detection of cyclotron absorption lines in the X-ray spectrum of a ULX provides an alternative way to identify the compact object as a neutron star. Among the non-pulsatingULXs, the presence of a cyclotron resonance scattering feature (CRSF) in the spectrum of M51 ULX-8 has been reported. In thepresent work, the magnetic field strength on the surface of the neutron star in M51 ULX-8 is inferred from the energy of the observedCRSF to estimate the beaming fraction in X-ray emission and more importantly the observable range for the elusive neutron-star spinperiod to be hopefully discovered by the forthcoming space missions in the near future.