Search for an extended VHE<i>γ</i>-ray emission from Mrk 421 and Mrk 501 with the MAGIC Telescope
Journal: Astronomy and Astrophysics
Year: 2010

Context. Part of the very high energy γ-ray radiation coming from extragalactic sources is absorbed through the pair production process on the extragalactic background light photons. Extragalactic magnetic fields alter the trajectories of these cascade pairs and, in turn, convert cosmic background photons to γ-ray energies by inverse Compton scattering. These secondary photons can form an extended halo around bright VHE sources.