1995A&A...298L..33B

We report evidence for intense MeV emission of the blazar-type AGN PKS 0208-512 from two COMPTEL observations in May-June 1993. No significant indication was seen during a series of earlier observations performed in the second half of 1991. EGRET detected high-energy γ-rays during both periods, with similar average fluxes in both (and a short flare in September 1991). We argue that the MeV emission from PKS 0208-512 seems to represent a distinct spectral component, characterized by either a bumped shape or strong time variability, or possibly both. This might be a valuable clue in our understanding of "MeV Blazars" (i.e. blazars that are exceptionally bright at MeV energies), suggesting a possibly transient nature of the MeV-blazar phenomenon. As a consequence, essentially all γ-rays blazars might contribute to the MeV bump in the diffuse cosmic background radiation during certain epochs rather than any specific sub-class.