Journal ArticleDOI
X-ray reflection from cold matter in the nuclei of active galaxies
Ken Pounds,K. Nandra,G. C. Stewart,Ian M. George,Andrew C. Fabian +4 more
- Vol. 344, Iss: 6262, pp 132-133
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TLDR
In this article, a composite spectrum from twelve Ginga observations of Seyfert-type active galactic nuclei has been used to model the hard X-ray power-law continuum in a slab (or perhaps a disk) of cold matter.Abstract:
THE evidence accumulated over the past few years for strong soft X-ray emission from active galactic nuclei1–3 has been interpreted as black body emission from the innermost stable region of an accretion disk feeding the putative black hole at the centre of the active nucleus, a view given strong support by the rapid variability of some soft X-ray components4. More recently, new X-ray data from the Exosat and Ginga satellites have revealed a second indicator of optically thick matter in the vicinity of the active nucleus, in the form of an iron K-fluorescence line at ≈6.4 keV (refs 5–8). We report the discovery of two further common features of continuum absorption and reflection, revealed in a composite spectrum from twelve Ginga observations of Seyfert-type active galactic nuclei. Most of these spectral features are shown to be well modelled by reprocessing of the hard X-ray power-law continuum in a slab (or perhaps a disk) of cold matter. There is also evidence for a substantial line-of-sight column of photoionized material.read more
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Journal ArticleDOI
Gravitationally redshifted emission implying an accretion disk and massive black hole in the active galaxy MCG-6-30-15
Yasuo Tanaka,K. Nandra,Andrew C. Fabian,Hajime Inoue,Chiko Otani,Tadayasu Dotani,Kiyoshi Hayashida,K. Iwasawa,Tsuneo Kii,Hideyo Kunieda,F. Makino,Makoto Matsuoka +11 more
TL;DR: In this paper, the authors detect relativistic effects in an X-ray emission line (the Kα line) from ionized iron in the galaxy MCG-6-30-15.
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A Structure for Quasars
TL;DR: In this article, a funnel-shaped thin shell outflow is proposed to explain the broad absorption line regions (BALRs) and the narrow "associated" ultraviolet and X-ray "ionized" absorbers (NALs).
Book ChapterDOI
Line Profiles from a Disk around a Rotating Black Hole
TL;DR: In this paper, the authors present a detailed analysis of the profiles of lines emitted from an accretion disk around a rotating black hole for a number of line emissivity laws, with an emphasis on cases where most of the flux originates from the inner regions of the disk.
Journal ArticleDOI
An XMM–Newton survey of broad iron lines in Seyfert galaxies
TL;DR: In this paper, the authors present an analysis of the X-ray spectra of a sample of 37 observations of 26 Seyfert galaxies observed by XMM-Newton in order to characterize their iron Kα emission.
Journal ArticleDOI
ASCA observations of Seyfert 1 galaxies: II. Relativistic Iron K-alpha emission
TL;DR: In this paper, the authors present evidence for widespread relativistic effects in the central regions of active galactic nuclei, including the presence of supermassive black holes in the centers of active galaxies.
References
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Journal ArticleDOI
X-ray fluorescence from the inner disc in Cygnus X-1
TL;DR: Les spectres RX de nombreuses sources de trous noirs en accretion suggerent la presence de matiere relativement froide entouree d'un plasma emetteur de RX dur.
Journal ArticleDOI
Effects of Cold Matter in Active Galactic Nuclei: A Broad Hump in the X-Ray Spectra
TL;DR: In this paper, a broad hump between about 10 keV and about 300 keV was predicted for the X-ray spectrum of active galactic nuclei (AGNs), and the predicted amplitude of the hump is about 0.1-0.5.
Journal ArticleDOI
The EXOSAT spectral survey of AGN
T. J. Turner,Ken Pounds +1 more
TL;DR: In this paper, the authors used Exosat observations of 48 hard X-ray selected Seyfert-type active galactic nuclei (AGN) to investigate the spectral properties of these nuclei.
Journal ArticleDOI
‘Cold’ material in non-thermal sources
P. W. Guilbert,Martin J. Rees +1 more
TL;DR: Les regions centrales des sources compactes telles que quasars ou noyaux actifs de galaxies contiennent une quantite non negligeable de gaz as discussed by the authors.
Journal ArticleDOI
Quasar energy distributions. I - Soft X-ray spectra of quasars
Belinda Jane Wilkes,Martin Elvis +1 more
TL;DR: In this paper, a correlation analysis shows that radio loudness, rather than redshift or luminosity, is fundamentally related to the X-ray slope, and the same effect is not present in BL Lac objects, implying that the effect is intrinsic to the quasars and is caused by a low-energy turnup in the quasar spectra.
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