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.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Get just this article for as long as you need it
$39.95
Prices may be subject to local taxes which are calculated during checkout
References
Arnaud, K. A. et al. Mon. Not. R. astr. Soc. 217, 105–114 (1985).
Wilkes, B. J. & Elvis, M. Astrophys. J. 323, 243–262 (1987).
Turner, T. J. & Pounds, K. A. Mon. Not. R. astr. Soc. 240, 833–880 (1989).
Turner, T. J. & Pounds, K. A. Mon. Not. R. astr. Soc. 232, 463–471 (1988).
Nandra, K. A., Pounds, K. A., Stewart, G. C., Fabian, A. C. & Rees, M. J. Mon. Not. R. astr. Soc. 236, 39–46P (1989).
Pounds, K. A. et al. Mon. Not. R. astr. Soc. 240, 769–784 (1989).
Nandra, K. A. et al. Mon. Not. R. astr. Soc. (in the press).
Matsuoka, M. et al. Astrophys. J. (submitted).
Pounds, K. A. Ann. N.Y. Acad. Sci. 302, 361–385 (1977).
Elvis, M. et al. Mon. Not. R. astr. Soc. 183, 129–157 (1978).
Tananbaum, H. et al. Astrophys. J. 223, 74–81 (1978).
Rothschild, R. E. et al. Astrophys. J. 269, 423–437 (1983).
Mushotzky, R. F. Adv. Space Res. 3, 10–18 (1984).
Guilbert, P. W. & Rees, M. J. Mon. Not. R. astr. Soc. 233, 475–484 (1988).
Perola, C. et al. Astrophys. J. 306, 508–521 (1986).
Lightman, A. P. & Zdziarski, A. A. Astrophys. J. 319, 643–661 (1987).
Yaqoob, T., Warwick, R. S. & Pounds, K. A. Mon. Not. R. astr. Soc. 236, 153–170 (1989).
Fabian, A. C. et al. Mon. Not. R. astr. Soc. 238, 729–736 (1989).
George, I. M., Nandra, K. A. & Fabian, A. C. Mon. Not. R. astr. Soc. 242, 28–31P (1990).
Lightman, A. P. & White, T. R. Astrophys. J. 335, 57–66 (1988).
Fabian, A. C., George, I. M., Miyoshi, S. & Rees, M. J. Mon. Not. R. astr. Soc. 242, 14–17P (1990).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pounds, K., Nandra, K., Stewart, G. et al. X-ray reflection from cold matter in the nuclei of active galaxies. Nature 344, 132–133 (1990). https://doi.org/10.1038/344132a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/344132a0
This article is cited by
-
Searching for Black Holes in Space
Space Science Reviews (2014)
-
Weighing super-massive black holes with narrow Fe Kα line
Science China Physics, Mechanics and Astronomy (2011)
-
X-ray Reflection
Space Science Reviews (2010)
-
X-ray absorption and reflection in active galactic nuclei
The Astronomy and Astrophysics Review (2009)
-
Rolling down from the 30 keV peak: Modelling the Hard X-Ray and γ-Ray Backgrounds
Experimental Astronomy (2006)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
