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dc.contributor.authorDewberry, Janosz Wen
dc.contributor.authorLatter, Henriken
dc.contributor.authorOgilvie, Gordonen
dc.date.accessioned2018-05-08T09:45:14Z
dc.date.available2018-05-08T09:45:14Z
dc.identifier.issn0035-8711
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/275602
dc.description.abstractThe high-frequency quasi-periodic oscillations (HFQPOs) that punctuate the light curves of X-ray binary systems present a window onto the intrinsic properties of stellar-mass black holes and hence a testbed for general relativity. One explanation for these features is that relativistic distortion of the accretion disc’s differential rotation creates a trapping region in which inertial waves (r-modes) might grow to observable amplitudes. Local analyses, however, predict that large-scale magnetic fields push this trapping region to the inner disc edge, where conditions may be unfavorable for r-mode growth. We revisit this problem from a pseudo-Newtonian but fully global perspective, deriving linearized equations describing a relativistic, magnetized accretion flow, and calculating normal modes with and without vertical density stratification. In an unstratified model, the choice of vertical wavenumber determines the extent to which vertical magnetic fields drive the r-modes toward the inner edge. In a global model fully incorporating density stratification, we confirm that this susceptibility to magnetic fields depends on disc thickness. Our calculations suggest that in thin discs, r-modes may remain independent of the inner disc edge for vertical magnetic fields with plasma betas as low as β ≈ 100 − 300. We posit that the appearance of r-modes in observations may be more determined by a competition between excitation and damping mechanisms near the ISCO than the modification of the trapping region by magnetic fields.
dc.description.sponsorshipJ. Dewberry thanks the Cambridge International and Vassar College De Golier Trusts for funding this work.
dc.publisherOxford University Press
dc.subjectaccretion, accretion discsen
dc.subjectblack hole physicsen
dc.subjectMHDen
dc.subjectmagnetic fieldsen
dc.subjectwavesen
dc.subjectX-rays: binariesen
dc.titleQuasi-periodic oscillations and the global modes of relativistic, MHD accretion discsen
dc.typeArticle
prism.endingPage4103
prism.issueIdentifier3en
prism.publicationNameMonthly Notices of the Royal Astronomical Societyen
prism.startingPage4085
prism.volume476en
dc.identifier.doi10.17863/CAM.22853
dcterms.dateAccepted2018-02-12en
rioxxterms.versionofrecord10.1093/mnras/sty385en
rioxxterms.versionAM*
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-02-12en
dc.contributor.orcidOgilvie, Gordon [0000-0002-7756-1944]
dc.identifier.eissn1365-2966
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idSTFC (ST/J001570/1)
pubs.funder-project-idSTFC (ST/P000673/1)
pubs.funder-project-idSTFC (ST/L000636/1)
cam.issuedOnline2018-02-14en
cam.orpheus.successThu Jan 30 13:01:28 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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