1. Department of Physics, KTH Royal Institute of Technology, and the Oskar Klein Centre for Cosmoparticle Physics, SE-10691 Stockholm, Sweden
2. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, 85748 Garching, Germany
3. Department of Physics, University College Cork, Cork, Ireland
4. Department of Physics, Bar-Ilan University, 52900 Ramat-Gan, Israel
5. International Center of Relativistic Astrophysics Network, Piazza della Repubblica 10, 65122 Pescara, Italy