ASCA Observations of Type 2 Seyfert Galaxies. II. The Importance of X-Ray Scattering and Reflection

We discuss the importance of X-ray scattering and Compton reflection in type 2 Seyfert Galaxies, based upon the analysis of ASCA observations of 25 such sources. Consideration of the iron Kα complex, [O III] line, and X-ray variability suggest that NGC 1068, NGC 4945, NGC 2992, Mrk 3, Mrk 463E, and Mrk 273 are dominated by reprocessed X-rays. We examine the properties of these sources in more detail. We find that the iron Kα complex contains significant contributions from neutral and high-ionization species of iron. Compton reflection, hot gas and starburst emission all appear to make significant contributions to the observed X-ray spectra. Mrk 3 is the only source in this subsample that does not have a significant starburst contamination. The ASCA spectrum below 3 keV is dominated by hot scattering gas with UX ~ 5, NH ~ 4 × 1023 cm-2. This material is more highly ionized than the zone of material comprising the warm absorber seen in Seyfert 1 galaxies, but may contain a contribution from shock-heated gas associated with the jet. Estimates of the X-ray scattering fraction cover 0.02%-5%. The spectrum above 3 keV appears to be dominated by a Compton reflection component, although there is evidence that the primary continuum component becomes visible close to ~10 keV.

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