[1] Max Planck Inst Kernphys, D-69117 Heidelberg, Germany
[2] Yerevan Phys Inst, Yerevan, Armenia
[3] UPS, CNRS, Ctr Etud Spatiale Rayonnements, Toulouse, France
[4] Univ Hamburg, Inst Expt Phys, Hamburg, Germany
[5] Humboldt Univ, Inst Phys, D-1086 Berlin, Germany
[6] CNRS, UMR 8102, LUTH, Meudon Sect, F-75700 Paris, France
[7] Univ Durham, Dept Phys, Durham DH1 3HP, England
[8] Ecole Polytech, CNRS, IN2P3, Lab Leprince Ringuet, F-91128 Palaiseau, France
[9] APC, Paris, France
[10] Dublin Inst Adv Studies, Dublin, Ireland
[11] Konigstuhl, Landessternwarte, Heidelberg, Germany
[12] Univ Montpellier 2, CNRS, IN2P, Lab Phys Theor & Astroparticules, F-34095 Montpellier, France
[13] Univ Grenoble 1, CNRS, ISNU, Lab Astrophys Grenoble, F-38041 Grenoble, France
[14] CE Saclay, CEA, DSM, DAPNIA, Gif Sur Yvette, France
[15] North West Univ, Unit Space Phys, Potchefstroom, South Africa
[16] Univ Paris 06, CNRS, IN2P3, Lab Phys Nucl & Hautes Energies, F-75252 Paris, France
[17] Univ Paris 07, F-75221 Paris, France
[18] Ruhr Univ Bochum, Lehrstuhl 4, Inst Theoret Phys, Bochum, Germany
[19] Charles Univ Prague, Inst Nucl & Particle Phys, Prague, Czech Republic
[20] Univ Namibia, Windhoek, Namibia