ИСТИНА

Extreme TeV blazars are active galactic nuclei that are believed to have spectral energy distribution peaked at an energy of ~1 TeV or above. These sources play an important role in extragalactic gamma-ray propagation studies. Gamma-rays with an energy E>1 TeV from distant (z>0.1) sources absorb on extragalactic background light (EBL) through pair production, \gamma\gamma→e^{+}e^{-}. During the last several years, several “anomalies” (effects not explained by the absorption and adiabatic losses) were observed: 1) an apparent excess of high-energy gamma-rays in the observable spectrum of some blazars 2) blazars with hard observed spectra are predominantly located towards the directions to voids in the large scale structure and 3) some blazars are extended sources in the GeV energy region. We argue that the account of intergalactic cascade process allows to qualitatively explain all these anomalies. On the other hand, we reject the hypothesis that all observable gamma-rays from extreme TeV blazars are due to intergalactic interactions of ultra-high energy protons or nuclei. Details of our calculations could be found in [A&A, 603, A59 (2017)].