OSSE Observations of Seyfert AGN

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Session 64 -- AGN Surveys and High Energy Spectra
Oral presentation, Thursday, January 13, 2:15-3:45, Salon IV Room (Crystal Gateway)

[64.03] OSSE Observations of Seyfert AGN

W.N.~Johnson, J.E.~Grove, R.L.~Kinzer, R.A.~Kroeger, J.D.~Kurfess, M.S.~Strickman (NRL), K.~McNaron-Brown (George Mason Univ), D.A.~Grabelsky, W.R.~Purcell, M.P.~Ulmer (Northwestern Univ), G.V.~Jung (USRA), and R.A.~Cameron (SAO)

In the first two years of the Compton Gamma Ray Observatory mission, the Oriented Scintillation Spectrometer Experiment (OSSE) has observed about two dozen Seyfert active galactic nuclei (AGN) selected from the HEAO$-1$ list (Rothschild et al.\ 1983) and intense X-ray sources detected by EXOSAT and Ginga. The OSSE observations in the 50~keV $-$ 10~MeV range indicate spectra which, on average, are significantly softer than the power law photon index of $\Gamma=1.7$ which is generally reported in the Xray band. The average spectrum is well described by exponential or thermal Comptonization models indicating a break in the spectrum near 100 keV. We summarize the OSSE observations of AGN and present the average Seyfert spectrum above 50 keV.

Rothschild, R.E., et al. 1983, Ap.\ J., 269, 423.

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