1303.5923 (D. A. Sanchez et al.)

Evidence for a cosmological effect in γ-ray spectra of BL Lacs    [PDF]

D. A. Sanchez, S. Fegan, B. Giebels

We update the list of GeV-TeV extragalactic \gamma-ray sources using the 2-year catalog from the Fermi-LAT and recent results ground-based \gamma-ray telescopes. Breaks in the spectra between the high energy (100 MeV 200 GeV) ranges, and their dependence on distance, are discussed in the context of absorption on the extragalactic background light (EBL). We calculate the size of the expected break using a model for the EBL and compare it to the data taking into account systematic uncertainties in the measurements. We develop a novel Bayeasian model to describe this dataset and use it to constrain two simple models for the EBL-induced breaks.

View original: http://arxiv.org/abs/1303.5923