[1] Leiden Univ, Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands
[2] Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus, Denmark
[3] Univ Sydney, Sch Phys A28, Sydney, NSW 2006, Australia
[4] Landessternwarte Heidelberg, ZAH, D-69117 Heidelberg, Germany
[5] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA
[6] Natl Astron Observ Japan, Okayama Astrophys Observ, Kamogatacho, Okayama 7190232, Japan
[7] Natl Astron Observ Japan, Mitaka, Tokyo 1818588, Japan
[8] Tokyo Inst Technol, Tokyo 1528550, Japan
[9] Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany
[10] Univ Paris XI CNRS, Inst Astrophys Spatiale, F-91405 Orsay, France
[11] Univ Paris 06, Univ Denis Diderot, Observ Paris, CNRS,LESIA, F-92195 Meudon, France
[12] Observ Cote Azur, UMT CNRS 6202, Lab Cassiopee, F-06304 Nice, France
[13] Inst Astrophys, CNRS, F-75014 Paris, France
[14] CEA Saclay, DAPNIA DSM Serv Astrophys, F-91191 Gif Sur Yvette, France
[15] CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France
[16] Osserv Astrofis Catania, INAF, I-95123 Catania, Italy
[17] Osserv Astron Padova, INAF, I-35122 Padua, Italy
[18] Telescopio Nazl Galileo, INAF, Santa Cruz de La Palma 38700, Spain
[19] Osserv Astron Capodimonte, INAF, I-80131 Naples, Italy
[20] Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland
[21] Gemini Observ, Hilo, HI 96720 USA
[22] Katholieke Univ Leuven, Inst Sterrekunde, B-3001 Heverlee, Belgium
[23] Univ Liege, Inst Astrophys & Geophys, B-4000 Cointe Ougree, Belgium
[24] Univ Geneva, Observ Geneva, CH-1290 Sauverny, Switzerland
[25] Univ Texas Austin, Dept Astron, Austin, TX 78712 USA
[26] Univ Texas Austin, McDonald Observ, Austin, TX 78712 USA
[27] Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA