1 Ocak 2022 Dergi makalesi Açık Erişim

Allak, S.; Akyuz, A.; Oralhan, I. Akkaya; Avdan, S.; Aksaker, N.; Vinokurov, A.; Soydugan, F.; Sonbas, E.; Dhuga, K. S.

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{
  "@context": "https://schema.org/", 
  "@id": 256679, 
  "@type": "ScholarlyArticle", 
  "creator": [
    {
      "@type": "Person", 
      "name": "Allak, S."
    }, 
    {
      "@type": "Person", 
      "name": "Akyuz, A."
    }, 
    {
      "@type": "Person", 
      "affiliation": "Erciyes Univ, Dept Astron & Space Sci, TR-38039 Kayseri, Turkey", 
      "name": "Oralhan, I. Akkaya"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Univ Cukurova, Space Sci & Solar Energy Res & Applicat Ctr UZAYM, TR-01330 Adana, Turkey", 
      "name": "Avdan, S."
    }, 
    {
      "@type": "Person", 
      "name": "Aksaker, N."
    }, 
    {
      "@type": "Person", 
      "affiliation": "Special Astrophys Observ Russian AS, Nizhnii Arkhyz 399167, Russia", 
      "name": "Vinokurov, A."
    }, 
    {
      "@type": "Person", 
      "name": "Soydugan, F."
    }, 
    {
      "@type": "Person", 
      "name": "Sonbas, E."
    }, 
    {
      "@type": "Person", 
      "affiliation": "George Washington Univ, Dept Phys, Washington, DC 20052 USA", 
      "name": "Dhuga, K. S."
    }
  ], 
  "datePublished": "2022-01-01", 
  "description": "We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton, and Swift-XRT archives, spanning the years 2000-2019.. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed over the time intervals of 100-2000 s in the 0.3-10 keV energy band. We find some evidence for the existence of bi-modality feature in the flux distribution of ULX-4. We identified two optical sources as possible counterparts within an error radius of 0.'' 18 at 95 per cent confidence level for ULX-4 based on the archival Hubble Space Telescope (HST)/ACS and HST/WFC3 data. Blackbody fits of the spectral energy distributions (SEDs) indicate the spectral type to be B-type stars. One of these counterparts exhibits a low-amplitude optical periodicity of 264 +/- 37 d in the F606W filter; if we assume this apparent periodicity is associated with the orbital motion of the donor, then it is more likely that the donor is a red supergiant satisfying the long periodicity and accretion via Roche lobe overflow. Consequently, the SED would then have to be interpreted as a superposition of emissions from a cold donor and a hot flow component, most likely from an accretion disc. If, on the other hand, the periodicity is superorbital in nature i.e. due to possible interactions of the compact object with a circumstellar disc, the donor could then be a Be/X star hosting a neutron star.", 
  "headline": "The transient ultraluminous X-ray source, ULX-4, in M51", 
  "identifier": 256679, 
  "image": "https://aperta.ulakbim.gov.tr/static/img/logo/aperta_logo_with_icon.svg", 
  "license": "http://www.opendefinition.org/licenses/cc-by", 
  "name": "The transient ultraluminous X-ray source, ULX-4, in M51", 
  "url": "https://aperta.ulakbim.gov.tr/record/256679"
}