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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 

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