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The evolution of AGN in the Hard X-rays from HELLAS

F. La Franca·F. Fiore·C. Vignali·A. Comastri·F. Pompilio·HELLAS consortium
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Abstract

We present optical spectroscopic identification of sources identified in the BeppoSAX MECS fields of the High Energy LLarge Area Survey (HELLAS). In total 62 sources from a sample of 115 brighter than F_{5-10keV}>5x10^{-14} cgs have been identified. We find a density of 13-21 sources/deg^2 at F_{5-10keV}>5x10^{-14} cgs, which contribute to 20-30 % of the hard X-ray background. Evidences are found for type 1 AGN being more absorbed with increasing redshift or luminosity. The low redshift (z<0.2) ratio of type 2 to type 1 AGN is 3+/-1.5, in agreement with the unified models for AGN. The luminosity function of type 1 AGN in the 2-10 keV band is preliminary fitted by a two-power law function evolving according to a pure luminosity evolution model: L~(1+z)^{2.2}.

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F. La Franca, F. Fiore, C. Vignali, A. Comastri, F. Pompilio, HELLAS consortium. 2000-11-01. The evolution of AGN in the Hard X-rays from HELLAS. https://arxiv.org/abs/astro-ph/0011008

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