[1] European So Observ, D-85748 Garching, Germany
[2] Danish Space Res Inst, DK-2100 Copenhagen O, Denmark
[3] Nord Opt Telescope, Santa Cruz De La Palma 38700, Spain
[4] Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark
[5] Univ Copenhagen, Astron Observ, DK-2100 Copenhagen O, Denmark
[6] Univ Oulu, Div Astron, Oulu 90014, Finland
[7] Univ Durham, Dept Phys, Durham DH1 3LE, England
[8] Natl Astron Observ Japan, SUBARU Telescope, Hilo, HI 96720 USA
[9] Univ Amsterdam, NL-1098 SJ Amsterdam, Netherlands
[10] Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium
[11] Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA
[12] US Naval Observ, Univ Space Res Assoc, Flagstaff, AZ 86002 USA
[13] Real Inst & Observ Armada, Secc Astron, Cadiz 11110, Spain
[14] Inst Astrofis Andalucia, CSIC, E-18080 Granada, Spain
[15] LAEFF, INTA, Madrid 28080, Spain
[16] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
[17] Astrophys Inst Potsdam, D-14482 Potsdam, Germany
[18] Univ Turku, Tuorla Observ, Piikkio 21500, Finland
[19] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[20] Univ Tromso, Dept Phys, Tromso, Norway
[21] Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England
[22] Kyoto Univ, Dept Phys, Sakyo Ku, Kyoto 6068502, Japan