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NuSTAR observation of the supergiant fast X-ray transient IGR J11215-5952 during its 2017 outburst

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dc.contributor.author Sidoli L.
dc.contributor.author Postnov K.
dc.contributor.author Tiengo A.
dc.contributor.author Esposito P.
dc.contributor.author Sguera V.
dc.contributor.author Paizis A.
dc.contributor.author Rodríguez Castillo G.A.
dc.date.accessioned 2021-02-24T20:31:39Z
dc.date.available 2021-02-24T20:31:39Z
dc.date.issued 2020
dc.identifier.issn 0004-6361
dc.identifier.uri https://dspace.kpfu.ru/xmlui/handle/net/160716
dc.description.abstract © ESO 2020. We report on the results of a NuSTAR observation of the supergiant fast X-ray transient pulsar IGR J11215-5952 during the peak of its outburst in June 2017. IGR J11215-5952 is the only SFXT undergoing strictly periodic outbursts (every 165 days). NuSTAR caught several X-ray flares, spanning a dynamic range of 100, and detected X-ray pulsations at 187.0 s, which is consistent with previous measurements. The spectrum from the whole observation is well described by an absorbed power law (with a photon index of 1.4), which is modified, above ∼7 keV, by a cutoff with an e-folding energy of ∼24 keV. A weak emission line is present at 6.4 keV, consistent with Kα emission from cold iron in the supergiant wind. The time-averaged flux is ∼1.5 × 10-10 erg cm-2 s-1 (3-78 keV, corrected for the absorption), translating into an average luminosity of about 9 × 1035 erg s-1 (1-100 keV, assuming a distance of 6.5 kpc). The NuSTAR observation allowed us to perform the most sensitive search for cyclotron resonant scattering features in the hard X-ray spectrum, resulting in no significant detection in any of the different spectral extractions adopted (time-averaged, temporally selected, spin-phase-resolved and intensity-selected spectra). The pulse profile showed an evolution with both the energy (3-12 keV energy range compared with 12-78 keV band) and the X-ray flux: a double-peaked profile was evident at higher fluxes (and in both energy bands), while a single-peaked, sinusoidal profile was present at the lowest intensity state achieved within the NuSTAR observations (in both energy bands). The intensity-selected analysis allowed us to observe an anti-correlation of the pulsed fraction with the X-ray luminosity. The pulse profile evolution can be explained by X-ray photon scattering in the accreting matter above magnetic poles of a neutron star at the quasi-spherical settling accretion stage.
dc.relation.ispartofseries Astronomy and Astrophysics
dc.subject Pulsars: individual: IGR J11215-5952
dc.subject Stars: neutron
dc.subject X-rays: binaries
dc.title NuSTAR observation of the supergiant fast X-ray transient IGR J11215-5952 during its 2017 outburst
dc.type Article
dc.relation.ispartofseries-volume 638
dc.collection Публикации сотрудников КФУ
dc.source.id SCOPUS00046361-2020-638-SID85089197249

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  • Публикации сотрудников КФУ Scopus [24551]
    Коллекция содержит публикации сотрудников Казанского федерального (до 2010 года Казанского государственного) университета, проиндексированные в БД Scopus, начиная с 1970г.

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