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

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dc.creatorLa Franca, F.
dc.creatorFiore, F.
dc.creatorVignali, C.
dc.creatorComastri, A.
dc.creatorPompilio, F.
dc.creatorconsortium, HELLAS
dc.date2000-11-01
dc.date.accessioned2026-07-07T01:56:20Z
dc.date.available2026-07-07T01:56:20Z
dc.descriptionWe 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}.
dc.description6 pages and 4 ps figures. To be published in Proc. of the Conference "the New Era of Wide-Field Astronomy", held in Preston (UK), 21-24 August 2000
dc.identifierhttps://arxiv.org/abs/astro-ph/0011008
dc.identifierhttp://arxiv.org/abs/astro-ph/0011008
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/1961
dc.subjectAstrophysics
dc.titleThe evolution of AGN in the Hard X-rays from HELLAS
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