dc.contributor.author Garcia, JA en dc.contributor.author Fabian, Andrew en dc.contributor.author Kallman, TR en dc.contributor.author Dauser, T en dc.contributor.author Parker, Michael en dc.contributor.author McClintock, JE en dc.contributor.author Steiner, JF en dc.contributor.author Wilms, J en dc.date.accessioned 2017-02-27T11:52:53Z dc.date.available 2017-02-27T11:52:53Z dc.date.issued 2016-10-11 en dc.identifier.issn 0035-8711 dc.identifier.uri https://www.repository.cam.ac.uk/handle/1810/262783 dc.description.abstract Current models of the spectrum of X-rays reflected from accretion discs around black holes and other compact objects are commonly calculated assuming that the density of the disc atmosphere is constant within several Thomson depths from the irradiated surface. An important simplifying assumption of these models is that the ionization structure of the gas is completely specified by a single, fixed value of the ionization parameter $\xi$, which is the ratio of the incident flux to the gas density. The density is typically fixed at $n_\text{e}$ = 10$^{15}$ cm$^{−3}$. Motivated by observations, we consider higher densities in the calculation of the reflected spectrum. We show by computing model spectra for $n_\text{e}$ $\gtrsim$ 10$^{17}$ cm$^{−3}$ that high-density effects significantly modify reflection spectra. The main effect is to boost the thermal continuum at energies $\lesssim$2 keV. We discuss the implications of these results for interpreting observations of both active galactic nuclei and black hole binaries. We also discuss the limitations of our models imposed by the quality of the atomic data currently available. dc.description.sponsorship JG and JEM acknowledge the support of a CGPS grant from the Smithsonian Institution. ACF acknowledges ERC Advanced Grant 340442 Feedback. JFS has been supported by the Einstein Fellowship grant PF5-160144. dc.language.iso en en dc.publisher Oxford University Press dc.subject accretion, accretion discs en dc.subject atomic processes en dc.subject line: formation en dc.subject radiative transfer en dc.subject relativistic processes en dc.subject X-rays: general en dc.title The effects of high density on the X-ray spectrum reflected from accretion discs around black holes en dc.type Article prism.endingPage 760 prism.issueIdentifier 1 en prism.publicationDate 2016 en prism.publicationName Monthly Notices of the Royal Astronomical Society en prism.startingPage 751 prism.volume 462 en dc.identifier.doi 10.17863/CAM.8073 dcterms.dateAccepted 2016-07-12 en rioxxterms.versionofrecord 10.1093/mnras/stw1696 en rioxxterms.version VoR en rioxxterms.licenseref.uri http://www.rioxx.net/licenses/all-rights-reserved en rioxxterms.licenseref.startdate 2016-10-11 en dc.contributor.orcid Fabian, Andrew [0000-0002-9378-4072] dc.contributor.orcid Parker, Michael [0000-0002-8466-7317] dc.identifier.eissn 1365-2966 rioxxterms.type Journal Article/Review en cam.issuedOnline 2016-07-14 en cam.orpheus.success Thu Jan 30 12:56:34 GMT 2020 - The item has an open VoR version. * rioxxterms.freetoread.startdate 2100-01-01
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