1. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
2. Institute for Cosmic Ray Research (ICRR), The University of Tokyo, Chiba 277-8583, Japan
3. INAF - Osservatorio Astronomico di Roma, Via di Frascati 33, I-00078 Monte Porzio Catone (Roma), Italy
4. Space Science Data Center - ASI, Via del Politecnico SNC, I-00133 Roma, Italy
5. Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, PL-00-716 Warsaw, Poland
6. Dipartimento di Fisica, Universita di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, I-00133 Roma, Italy
7. Instituto de Astrofísica de Canarias, Calle Via Lactea, E-38205 La Laguna, Tenerife, Spain
8. Universidad de La Laguna, Dpto. Astrofísica, E-38206 La Laguna, Tenerife, Spain
9. INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli, Italy
10. Dominion Astrophysical Observatory, NRC-Herzberg, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada