2010/01/13 by Marco Roncadelli, Roncadelli, Marco, Alessandro De Angelis +3
Physics and Astronomy · #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #astro-ph.CO #astro-ph.HE #hep-ph
paper · pdf · doi:10.48550/arxiv.1001.2171
4 pages, 1 image Proceeding of the Rencontres de Moriond on "Very High Energy Phenomena in the Universe", La Thuile, Italy, 1-8 February 2009 (to be published in the Proceedings)
Early indications by H.E.S.S. and the subsequent detection of blazar 3C279 by MAGIC show that the Universe is more transparent to very-high-energy gamma rays than previously thought. We demonstrate that this circumstance can be reconciled with standard blazar emission models provided that photon oscillations into a very light Axion-Like Particle occur in extragalactic magnetic fields. A quantitative estimate of this effect indeed explains the observed spectrum of 3C279. Our prediction can be tested by the satellite-borne Fermi/LAT detector as well as by the ground-based Imaging Atmospheric Cherenkov Telescopes H.E.S.S., MAGIC, CANGAROO III, VERITAS and by the Extensive Air Shower arrays ARGO-YBJ and MILAGRO.