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dc.contributor.authorThomsen, LL
dc.contributor.authorDai, L
dc.contributor.authorKara, E
dc.contributor.authorReynolds, Christopher
dc.date.accessioned2022-02-02T15:51:07Z
dc.date.available2022-02-02T15:51:07Z
dc.date.issued2022-02-01
dc.date.submitted2021-09-07
dc.identifier.issn0004-637X
dc.identifier.otherapjac3df3
dc.identifier.otherac3df3
dc.identifier.otheraas34584
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/333559
dc.description.abstractX-ray reverberation is a powerful technique which maps out the structure of the inner regions of accretion disks around black holes using the echoes of the coronal emission reflected by the disk. While the theory of X-ray reverberation has been developed almost exclusively for standard thin disks, recently reverberation lags have been observed from likely super-Eddington accretion sources such as the jetted tidal disruption event Swift J1644+57. In this paper, we extend X-ray reverberation studies into the super-Eddington accretion regime, focusing on investigating the lags in the Fe K{\alpha} line region. We find that the coronal photons are mostly reflected by the fast and optically thick winds launched from super-Eddington accretion flow, and this funnel-like reflection geometry produces lag-frequency and lag-energy spectra with unique characteristics. The lag-frequency spectra exhibits a step-function like decline near the first zero-crossing point. As a result, the shape of the lag-energy spectra remains almost independent of the choice of frequency bands and linearly scales with the black hole mass for a large range of parameter spaces. Not only can these morphological differences be used to distinguish super-Eddington accretion systems from sub-Eddington systems, they are also key for constraining the reflection geometry and extracting parameters from the observed lags. When explaining the X-ray reverberation lags of Swift J1644+57, we find that the super-Eddington disk geometry is preferred over the thin disk, for which we obtain a black hole mass of 5-6 million solar masses and a coronal height around 10 gravitational radii by fitting the lag spectra to our modeling.
dc.languageen
dc.publisherAmerican Astronomical Society
dc.subject330
dc.subjectHigh-Energy Phenomena and Fundamental Physics
dc.titleRelativistic X-Ray Reverberation from Super-Eddington Accretion Flow
dc.typeArticle
dc.date.updated2022-02-02T15:51:07Z
prism.issueIdentifier2
prism.publicationNameAstrophysical Journal
prism.volume925
dc.identifier.doi10.17863/CAM.80979
dcterms.dateAccepted2021-11-27
rioxxterms.versionofrecord10.3847/1538-4357/ac3df3
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.contributor.orcidThomsen, LL [0000-0003-4256-7059]
dc.contributor.orcidDai, L [0000-0002-9589-5235]
dc.contributor.orcidKara, E [0000-0003-0172-0854]
dc.contributor.orcidReynolds, Christopher [0000-0002-1510-4860]
dc.identifier.eissn1538-4357
dc.publisher.urlhttp://dx.doi.org/10.3847/1538-4357/ac3df3
pubs.funder-project-idScience and Technology Facilities Council (ST/S000623/1)
pubs.funder-project-idEuropean Commission Horizon 2020 (H2020) ERC (834203)
cam.issuedOnline2022-02-02


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