The Comptonization of accretion disc X-ray emission: consequences for X-ray reflection and the geometry of AGN coronae

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dc.creator Wilkins, D. R.
dc.creator Gallo, Luigi C.
dc.date.accessioned 2017-08-30T15:02:59Z
dc.date.available 2017-08-30T15:02:59Z
dc.date.issued 2015-03-21
dc.identifier.issn 0035-8711
dc.identifier.uri http://library2.smu.ca/handle/01/27064
dc.description Publisher's version/PDF
dc.description.abstract We consider the Comptonization of the photons that make up the relativistically blurred reflection that is commonly detected from the accretion discs of active galactic nuclei by the coronae of energetic particles believed to give rise to the powerful X-ray continua by the inverse-Compton scattering of thermal seed photons from the disc. Recent measurements of the emissivity profiles of accretion discs as well as reverberation time lags between the primary X-ray continuum and the reflection suggest that this corona is situated at a low height above the disc and extends radially, tens of gravitational radii over the disc surface, hence should also Compton scatter the reflected X-rays. We find that the detection of blurred reflection from as close in as the innermost stable circular orbits (ISCOs) of maximally rotating black holes is consistent with such coronae, but requires that the corona be patchy, consisting perhaps of a number of isolated flares throughout the region. Considering only the requirement that it be possible to detect reflection from the ISCO, we find that at any given moment, the covering fraction of the inner part of the accretion disc by the corona needs to be less than 85 per cent, although the detection of ‘reflection-dominated’ spectra in which the total reflected flux exceeds that seen in the continuum requires covering fractions as low as 50 or 25 per cent. en_CA
dc.language.iso en en_CA
dc.publisher Oxford University Press en_CA
dc.relation.uri http://dx.doi.org/10.1093/mnras/stu2524
dc.rights This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
dc.subject.lcsh X-ray sources, Galactic -- Accretion
dc.subject.lcsh Accretion (Astrophysics)
dc.subject.lcsh Active galactic nuclei
dc.title The Comptonization of accretion disc X-ray emission: consequences for X-ray reflection and the geometry of AGN coronae en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Monthly Notices of the Royal Astronomical Society 448(1), 703-712. (2015) en_CA


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This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
 
Published Version: http://dx.doi.org/10.1093/mnras/stu2524
 
 

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