[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[2] CALTECH, Pasadena, CA 91125 USA
[3] Univ Oxford, Dept Phys, Oxford OX1 3RH, England
[4] Osservatorio Astron Bologna, INAF, I-40127 Bologna, Italy
[5] Ist Nazl Fis Nucl, Sez Bologna, I-40127 Bologna, Italy
[6] Space Telescope Sci Inst, Baltimore, MD 21208 USA
[7] Acad Sinica, Inst Astron & Astrophys, Taipei 10617, Taiwan
[8] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA
[9] Osserv Astron Trieste, INAF, I-34143 Trieste, Italy
[10] Ohio State Univ, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA
[11] Ohio State Univ, Dept Phys, Columbus, OH 43210 USA
[12] Univ Munich, D-81679 Munich, Germany
[13] Max Planck Inst Extraterr Phys, D-85748 Garching, Germany
[14] Heidelberg Univ, Zentrum Astron, Inst Theoret Astrophys, D-69120 Heidelberg, Germany
[15] Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, Denmark
[16] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
[17] CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain
[18] CSIC, IEEC, Inst Ciencies Espai, E-08193 Bellaterra, Barcelona, Spain
[19] UCL, Dept Phys & Astron, London WC1E 6BT, England
[20] Osserv Astron Capodimonte, INAF, I-80131 Naples, Italy
[21] Univ Ferrara, Dipartimento Fis & Sci Terra, I-44122 Ferrara, Italy
[22] Leiden Univ, Leiden Observ, NL-2333 Leiden, Netherlands
[23] Univ Basque Country, UPV EHU, Dept Theoret Phys & Hist Sci, E-48080 Bilbao, Spain
[24] Basque Fdn Sci, Ikerbasque, Santiago 48011, Chile
[25] Pontificia Univ Catolica Chile, Fac Fis, Inst Astrofs, Santiago 22, Chile
[26] Pontificia Univ Catolica Chile, Ctr Astroingn, Dept Astron & Astrofis, Santiago, Chile
[27] Observ Carnegie Inst Washington, Pasadena, CA 91101 USA
[28] Univ Durham, Inst Computat Cosmol, Durham DH1 3LE, England
[29] Siena Coll, Dept Phys & Astron, Loudonville, NY 12211 USA
[30] Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA
[31] Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid, Spain
[32] Observ Paris, CNRS, LERMA, UMR 8112, F-75014 Paris, France