An excess of extreme TeV blazars from the Fermi LAT distribution on the voidiness parameter

Abstract

Recently it was found that Fermi LAT blazars with relatively hard (γ <3) observed spectra above 10 GeV are predominantly located towards the directions to voids in the large scale structure and, moreover, the observed flux of E >10 GeV γ-rays is usually greater for the case of such directions. This effect may be interpreted in the framework of the "electromagnetic cascade model" (T.A. Dzhatdoev et al., A&A, 603, A59 (2017)). Namely, the secondary (cascade) component significantly enhances the observable flux in the 10-500 GeV energy region, rendering the sources brighter in this energy range. The model predicts the existence of a new population of blazars with very hard spectra in the 10 GeV-1 TeV energy region that could be discovered in future by the CTA observatory.