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E.C. Moran, A.V. Filippenko (Berkeley), L.E. Kay (Columbia/Barnard)
It is frequently proposed that the majority of the cosmic X-ray background (XRB) is produced by heavily obscured AGNs. If this scenario is correct, the integrated 1--10 keV spectrum of such objects, which are expected to have Seyfert~2 optical classifications, should be as flat as (or flatter than) the spectrum of the XRB itself. While observations have shown that the intrinsically steep X-ray spectra of a number of Seyfert~2s are flattened due to transmission through dense material, it remains to be seen if this applies to all Seyfert~2 galaxies, and if their spectra, which display considerable diversity, combine to yield a spectrum whose shape is similar to that of the XRB. To investigate this issue, we have carried out an ASCA\/ survey of a distance-limited sample of 30 nearby type~2 Seyfert galaxies. The majority of the objects in the sample are detected. Using the full dataset, we have constructed an unbiased, luminosity-weighted composite Seyfert~2 X-ray spectrum, which we compare to the spectrum of the XRB measured by ASCA. In addition, we have recently completed an optical spectropolarimetry survey of this entire sample of Seyfert~2s, which has revealed evidence for polarized broad emission lines in 11 of the objects. Using these results, we have compiled hard X-ray detection statistics and composite X-ray spectra separately for Seyfert~2s with and without evidence for polarized broad emission lines, which provides valuable insight into the issue of Seyfert unification.