Cascade Model of an Anomaly in Blazar Spectra at Very High Energy

Abstract

It is well known that the effect of gamma-ray absorption on extragalactic background light (EBL) is weakly expressed in the spectra of some blazars. It is shown that a secondary component generated by electromagnetic cascades might considerably decrease the statistical significance of this anomaly. Observational results indicate the existence of the cascade component in the spectra of extragalactic gamma-ray sources, thus supporting the proposed model.Comment: 6 pages, 2 figures. Original Russian text: Izvestiya Rossiiskoi Akademii Nauk, 79, 363 (2015) (In print) (author's translation