Compton reflection and iron fluorescence in AGN and GBHCs

dc.creatorReynolds, C. S.
dc.date1998-10-01
dc.date.accessioned2026-07-07T02:28:10Z
dc.date.available2026-07-07T02:28:10Z
dc.descriptionAny cold, optically-thick matter in the vicinity of an accreting black hole, such as the accretion disk, can intercept and reprocess some fraction of the hard X-ray continuum emission, thereby imprinting atomic features into the observed spectrum. This process of `X-ray reflection' primarily gives rise to a broad reflection `hump' peaking at 30keV and an iron emission line at 6.4keV. In this review, I briefly describe the physics of this process before reviewing the observations of these features in active galactic nuclei (AGN) and Galactic black hole candidates (GBHCs). In some AGN, Seyfert galaxies in particular, the iron line is found to be very broad and asymmetric. It is believed that such lines arise from the innermost regions of the accretion disk, with mildly-relativistic Doppler shifts and gravitational redshifts combining to produce the line profile. Hence, such lines give us a direct observational probe of the region within several gravitational radii of the black hole. The complications that plague similar studies of GBHCs, such as disk ionization and the possibly of inner disk disruption, are also addressed. I conclude with a discussion of iron line reverberation, i.e. temporal changes of the iron line as `echos' of large X-ray flares sweep across the accretion disk. It is shown that interesting reverberation effects, such as a definitive signature of extremal Kerr geometry, is within reach of high throughput spectrometers such as Constellation-X.
dc.description15 pages, 13 postscript figures. Invited review at the workshop on "High Energy Processes in Accreting Black Holes", Eds. J. Poutanen & R. Svensson (Graftavallen, Sweden), June29 - July 4, 1998
dc.identifierhttps://arxiv.org/abs/astro-ph/9810018
dc.identifierhttp://arxiv.org/abs/astro-ph/9810018
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/13007
dc.subjectAstrophysics
dc.titleCompton reflection and iron fluorescence in AGN and GBHCs
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