A Simple Analytic Treatment of the Intergalactic Absorption Effect in Blazar Gamma-Ray Spectra

F. W. Stecker, S. T. Scully
2006 Astrophysical Journal  
We derive a new and user friendly simple analytic approximation for determining the effect of intergalactic absorption in the energy range 0.2-2 TeV and the redshift range 0.05-0.4. In these ranges, the form of the absorption coeeficient is approximately logarithmic in energy. The effect of this energy dependence is to steepen intrinsic source spectra such that a source with an approximate power-law intrinsic spectrum in this energy range with spectral index Γ_s is steepened to a power-law with
more » ... an observed spectral index Γ_o = Γ_s + ΔΓ (z) where ΔΓ (z) is a linear function of z in the redshift range 0.05-0.4. We apply this approximation to the spectra of seven TeV blazars.
doi:10.1086/509885 fatcat:smsjwvlyfvawfowhqdxwsxuzi4