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dc.contributor.authorBreeveld, Alice
dc.contributor.authorde Pasquale, Massimiliano
dc.contributor.authorHan, Qin
dc.contributor.authorBrown, Peter J.
dc.contributor.authorTohuvavohu, Aaron
dc.contributor.authorBurrows, David N.
dc.contributor.authorTroja, Eleonora
dc.contributor.authorSiegel, Michael
dc.contributor.authorSbarufatti, Boris
dc.contributor.authorPage, Kim L.
dc.contributor.authorPage, Mat J.
dc.contributor.authorOsborne, Julian P.
dc.contributor.authorMarkwardt, Craig
dc.contributor.authorLevan, Andrew
dc.contributor.authorCampana, Sergio
dc.contributor.authorCenko, S. Bradley
dc.contributor.authorKuin, N. Paul M.
dc.contributor.authorWu, Kinwah
dc.contributor.authorOates, Samantha
dc.contributor.authorLien, Amy
dc.contributor.authorEmery, Sam
dc.contributor.authorKennea, Jamie A.
dc.date.accessioned2021-03-04T09:01:29Z
dc.date.available2021-03-04T09:01:29Z
dc.date.issued2019
dc.identifier.citationKuin N. P. M. , Wu K., Oates S., Lien A., Emery S., Kennea J. A. , de Pasquale M., Han Q., Brown P. J. , Tohuvavohu A., et al., "Swift spectra of AT2018cow: a white dwarf tidal disruption event?", MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, cilt.487, sa.2, ss.2505-2521, 2019
dc.identifier.issn0035-8711
dc.identifier.othervv_1032021
dc.identifier.otherav_664fae36-8d17-4a77-8034-6e34b1793961
dc.identifier.urihttp://hdl.handle.net/20.500.12627/71060
dc.identifier.urihttps://doi.org/10.1093/mnras/stz053
dc.description.abstractThe bright transient AT2018cow has been unlike any other known type of transient. Its high brightness, rapid rise and decay, and initially nearly featureless spectrum are unprecedented and difficult to explain using models for similar burst sources. We present evidence for faint gamma-ray emission continuing for at least 8 d, and featureless spectra in the ultraviolet bands - both unusual for eruptive sources. The X-ray variability of the source has a burst-like character. The UV-optical spectrum does not show any CNO line but is well described by a blackbody. We demonstrate that a model invoking the tidal disruption of a 0.1-0.4 M-circle dot helium white dwarf (WD) by a 10(5)-10(6) M-circle dot black hole located in the outskirts of galaxy Z 137-068 could provide an explanation for most of the characteristics shown in the multiwavelength observations. A blackbody-like emission is emitted from an opaque photosphere, formed by the debris of the WD disruption. Broad features showing up in the optical/infrared spectra in the early stage are probably velocity broadened lines produced in a transient high-velocity outward moving cocoon. The asymmetric optical/infrared lines that appeared at a later stage are emission from an atmospheric layer when it detached from thermal equilibrium with the photosphere, which undergoes more rapid cooling. The photosphere shrinks when its temperature drops, and the subsequent infall of the atmosphere produced asymmetric line profiles. Additionally, a non-thermal jet might be present, emitting X-rays in the 10-150 keV band.
dc.language.isoeng
dc.subjectASTRONOMİ VE ASTROFİZİK
dc.subjectUzay bilimi
dc.subjectTemel Bilimler (SCI)
dc.subjectFizik
dc.subjectAstronomi ve Astrofizik
dc.subjectTemel Bilimler
dc.titleSwift spectra of AT2018cow: a white dwarf tidal disruption event?
dc.typeMakale
dc.relation.journalMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
dc.contributor.departmentUniversity Of London , ,
dc.identifier.volume487
dc.identifier.issue2
dc.identifier.startpage2505
dc.identifier.endpage2521
dc.contributor.firstauthorID266794


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