[1] Max Planck Inst Extraterr Phys, D-85748 Garching, Germany
[2] CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France
[3] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England
[4] Univ Hertfordshire, Sch Phys Astron & Math, Hatfield AL10 9AB, Herts, England
[5] Univ Trieste, Dipartimento Astron, I-34133 Trieste, Italy
[6] Univ Durham, Dept Phys, Inst Computat Cosmol, Durham DH1 3LE, England
[7] Liverpool John Moores Univ, Liverpool L3 5UX, Merseyside, England
[8] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
[9] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[10] Osservatorio Astron Brera Merate, INAF, I-23807 Merate, Italy
[11] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
[12] Max Planck Inst Radioastron, D-53121 Bonn, Germany
[13] Univ Illinois, Dept Phys, Urbana, IL 61801 USA
[14] Tokyo Univ Sci, Dept Phys, Shinjuku Ku, Tokyo 1628601, Japan
[15] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA
[16] Tokyo Metropolitan Univ, Dept Phys, Hachioji, Tokyo 1920397, Japan
[17] Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark
[18] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile
[19] Univ Bonn, AIfA, D-53121 Bonn, Germany
[20] Univ Sussex, Ctr Astron, Brighton BN1 9QJ, E Sussex, England
[21] European So Observ, D-85748 Garching, Germany
[22] Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15217 USA
[23] Univ Porto, Dept Matemat Aplicada, P-4169007 Porto, Portugal
[24] Univ Porto, Fac Ciencias, P-4169007 Porto, Portugal
[25] Univ Porto, Ctr Astrofis, P-4150762 Porto, Portugal