2010A&A...511A..11Y

Our goal is to understand the nature of blazars and the mechanisms for generating high-energy γ-rays, through investigation of the blazar 3C 66A. We model the high-energy spectrum of 3C 66A, which was observed recently with the Fermi-LAT and VERITAS telescopes. The spectrum has a hard change from the energy range of 0.2-100GeV to 200-500GeV in recent almost contemporaneous observations of two telescopes. The de-absorbed VERITAS spectrum depends strongly on redshift, which is highly uncertain. If z=0.444 is adopted, we are able to use the SSC model to produce the Fermi-LAT component and the EC model to the VERITAS component. However, if z=0.1, the intrinsic VERITAS spectrum will be softer, and there will be a smooth link between the Fermi-LAT and VERITAS spectra that can be explained using an SSC model.