Astrophys. J., 707, 778-786 (2009/December-2)
Balancing the cosmic energy budget: the cosmic X-ray background, blazars, and the Compton thick active galactic nucleus fraction.
DRAPER A.R. and BALLANTYNE D.R.
Abstract (from CDS):
At energies ≳2 keV, active galactic nuclei (AGNs) are the source of the cosmic X-ray background (CXB). For AGN population synthesis models to replicate the peak region of the CXB (∼30 keV), a highly obscured and therefore nearly invisible class of AGN, known as Compton thick (CT) AGN, must be assumed to contribute nearly a third of the CXB. In order to constrain the CT fraction of AGNs and the CT number density we consider several hard X-ray AGN luminosity functions and the contribution of blazars to the CXB. Following the unified scheme, the radio AGN luminosity function is relativistically beamed to create a radio blazar luminosity function. An average blazar spectral energy density model is created to transform radio luminosity to X-ray luminosity. We find the blazar contribution to the CXB to be 12% in the 0.5-2 keV band, 7.4% in the 2-10 keV band, 8.9% in the 15-55 keV band, and 100% in the MeV region. When blazars are included in CXB synthesis models, CT AGNs are predicted to be roughly one-third of obscured AGNs, in contrast to the prediction of one half if blazars are not considered. Our model implies a BL Lac X-ray duty cycle of ∼13%, consistent with the concept of intermittent jet activity in low power radio galaxies.
galaxies: active - galaxies: jets - quasars: general - X-rays: diffuse background
In table 1: 2052-447 is a misprint for 2052-474 which is QSO B2052-474 in SIMBAD.
View the reference in ADS
To bookmark this query, right click on this link: simbad:2009ApJ...707..778D and select 'bookmark this link' or equivalent in the popup menu