2008A&A...479...41K -
Astronomy and Astrophysics, volume 479, 41-47 (2008/2-3)
BL Lacertae contribution to the extragalactic gamma-ray background.
KNEISKE T.M. and MANNHEIM K.
Abstract (from CDS):
Very high energy gamma-rays from blazars traversing cosmological distances through the metagalactic radiation field can convert into electron-positron pairs in photon-photon collisions. The converted gamma-rays initiate electromagnetic cascades driven by inverse-Compton scattering off the microwave background photons. Using a model for the time-dependent metagalactic radiation field consistent with all currently available far-infrared-to-optical data, we calculate the cascade contribution from faint, unresolved high- and low-peaked blazars to the extragalactic gamma-ray background as measured by EGRET. For low-peaked blazars, we adopt a spectral index consistent with the mean spectral index of EGRET detected blazars, and the EGRET luminosity function. For high-peaked blazars, we adopt template spectra matching prototype sources observed with air-Cherenkov telescopes up to 30TeV, and a luminosity function based on X-ray measurements. The low number of ∼20 for nearby high-peaked blazars with a flux exceeding 10–11/cm2/s above 300GeV inferred from the luminosity function is consistent with the results from air-Cherenkov telescope observations. Including the cascade emission from higher redshifts, the total high-peaked blazar contribution to the observed gamma-ray background at GeV energies can account for ∼30%.
Abstract Copyright:
∼
Journal keyword(s):
galaxies: BL Lacertae objects: general - cosmology: diffuse radiation - gamma rays: observations
CDS comments:
Paragraph 4.1 1ES 1995+650 is a misprint for 1ES 1959+650.
Simbad objects:
9
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2008A&A...479...41K and select 'bookmark this link' or equivalent in the popup menu