Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-14T22:52:46.985Z Has data issue: false hasContentIssue false
  • English
  • Français

The EXOSAT Spectral Survey of Emission Line AGN

Published online by Cambridge University Press:  07 August 2017

K. A. Pounds  and
T. J. Turner
K. A. Pounds
Affiliation:
X-ray Astronomy Group, Department of Physics, University of Leicester, Leicester, LE1 7RH, England
T. J. Turner
Affiliation:
X-ray Astronomy Group, Department of Physics, University of Leicester, Leicester, LE1 7RH, England

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Results are presented from EXOSAT observations of Seyfert type active galactic nuclei (AGN). The sample chosen for study are 48 hard X-ray selected Seyfert type AGN, including all 30 of the emission line AGN in the Piccinotti sample. Combining EXOSAT LE and ME data has allowed us to obtain broad band X-ray spectra over the range 0.1–10 keV. Spectra in the ∼ 2–10 keV range are found to be well described by a simple power-law. The distribution of spectral indices across the sample can be approximated by a Gaussian distribution of mean energy index ∝ = 0.70 with σ∝ = 0.17 although not all individual spectra are consistent with this mean at the 90% confidence level. EXOSAT has also revealed a substantial number of sources with complex soft X-ray spectra. These include spectra with a second spectral component at soft X-ray energies and sources with “leaky” absorbing columns. Evidence that soft excess components occur in at least 50% of Seyfert type AGN together with detection of rapid variability in the soft component provides quantitative support for an accretion disc model for AGN.

Type
Part 3: X-rays and the Central Source
Information
Symposium - International Astronomical Union , Volume 134: Active Galactic Nuclei , 1989 , pp. 155 - 160
Copyright
Copyright © Kluwer 1989 

References

Arnaud, K.A. et al: 1985, Mon. Not. R. astr. Soc. 217, 105.Google Scholar
Barr, P., 1987, Mon. Not. R. astr. Soc. 223 29P.CrossRefGoogle Scholar
Elvis, M., et al: 1978, Mon. Not. R., astr. Soc. 183, 129.Google Scholar
Guilbert, P.W., Fabian, A.C. and Rees, M.J.: 1983, Mon. Not. R. astr. Soc. 205, 593.Google Scholar
Heiles, C.: 1975, Astron. & Astrophys. Suppl. 20, 37.Google Scholar
Holt, S.S. et al: 1980, Astrophys. J. 241, L13.Google Scholar
de Korte, P. et al: 1981, Sp. Sci. Rev. 30, 495.Google Scholar
Kriss, G.A., Canizares, C.R. and Ricker, G.R.: 1980, Astrophys.J. 242, 292.Google Scholar
McHardy, I.M., Lawrence, A., Pye, J.P. and Pounds, K.A.: 1981, Mon. Not. R. astr. Soc. 197, 893.CrossRefGoogle Scholar
Morini, M. et al: 1986, Astrophys. J. 307, 486.Google Scholar
Morrison, R. and McCammon, D.: 1983, Asrophys. J. 270, 119.Google Scholar
Mushotzky, R.F.: 1984, Adv. Space Research, 3, 10.Google Scholar
Pan, H.C., Stewart, G.C. and Pounds, K.A.: 1988, Preprint.Google Scholar
Perola, G.C. et al: 1986, Astrophys.J. 306, 508.Google Scholar
Petre, R., Mushotzky, R.F., Krolik, J.H. and Holt, S.S.: 1984, Astrophys. J. 280, 499.Google Scholar
Piccinotti, G. et al: 1981, Astrophys.J. 253, 485.Google Scholar
Pounds, K.A.: 1977, in “Eighth Texas Symposium on Relativistic Astrophysics”, Ed. Papagiannis, D. Ann. New York Acad. Sci. 302, 361.Google Scholar
Pounds, K.A., Warwick, R.S., Culhane, J.L. and De Korte, P.J.: 1986a, Mon. Not. R. astr. Soc. 218, 685.Google Scholar
Pounds, K.A., Stanger, V.J., Turner, T.J., King, A.R. and Czerny, B.: 1986b, Mon. Not. R. astr. Soc. 224 443.Google Scholar
Reichert, G.A., Mushotzky, R.F., Petre, R. and Holt, S.S.: 1985, Astrophys. J. 296, 69.Google Scholar
Tananbaum, H., Avni, Y., Green, R.F., Schmidt, M. and Zamorani, G.: 1986, Astrophys. J., 305, 57.Google Scholar
Turner, M.J.L. et al: 1981, Sp. Sci. Rev. 30, 513.Google Scholar
Urry, M., Kruper, J.S., Canizares, C.R., Rohan, M.L. and Oberhardt, M.L.: 1987, in “Variability of Galactic and Extragalactic X-ray Sources”, pp. 15–28, Ed. Treves, A., A.A.D.A., Milano.Google Scholar
Yaqoob, T., Warwick, R.S. and Pounds, K.A.: 1988, Mon. Not. R. astr. Soc. - in press.Google Scholar
Zdziarski, A.A. and Lightman, A.P.: 1985, Astrophys. J. 294, L79.Google Scholar