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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

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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