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Soft X-rays of AGN: Emission from Accretion Disks?

Published online by Cambridge University Press:  12 April 2016

R. Staubert
Affiliation:
Institut für Astronomie und Astrophysik, Astronomie, Universität Tübingen, Germany
T. Dörrer
Affiliation:
Institut für Astronomie und Astrophysik, Astronomie, Universität Tübingen, Germany
C. Müller
Affiliation:
Institut für Astronomie und Astrophysik, Astronomie, Universität Tübingen, Germany
P. Friedrich
Affiliation:
Astrophysikalisches Institut Potsdam, Germany
H. Brunner
Affiliation:
Astrophysikalisches Institut Potsdam, Germany

Extract

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Soft X-ray spectra of many Active Galactic Nuclei (AGN) show structure which suggests excess emission at low energies, mostly below 1 keV. This was confirmed by the ROSAT spectra (0.1–2.4 keV) AGN in our samples which generally have steeper power law spectra than the canonical index of 0.7. The soft excess component may be the high energy tail of the big blue bump which in turn may be due to the integrated emission from an accretion disk around the central black hole.

We discuss results of our spectral analysis of two different samples of AGN: 1) QSO/Seyfert-I from the ROSAT All Sky Survey (RASS) and 2) radio-quiet QSO from ROSAT Pointed Observations. The ROSAT data are combined with UV Data from IUE and hard X-ray data from various hard X-ray missions.

Type
Part 15. Poster Papers
Copyright
Copyright © Astronomical Society of the Pacific 1997

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