Abstract
AT least 20% of all Type I Seyfert galaxies are detectable1,2 (at the comparable Ariel 5 and Uhuru sensitivities) as X-ray sources in the ∼2–10 keV band. Both the Ariel 5 and Uhuru results indicate the X-ray luminosity function is quite steep (dN/dL∼L−2) so that more sensitive HEAO X-ray detectors may reveal that nearly all Type I Seyfert galaxies are X-ray sources. It is suggested here that the diffuse background spectrum observed at hard X-ray and γ-ray energies can be accounted for by Seyferts, given their individual (hard) spectra.
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GRINDLAY, J. Diffuse γ-ray background from Seyfert galaxies. Nature 273, 211 (1978). https://doi.org/10.1038/273211a0
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DOI: https://doi.org/10.1038/273211a0
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