[1] Univ Calif Davis, Davis, CA 95616 USA
[2] Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA
[3] Univ Sussex, Ctr Astron, Brighton BN1 9QJ, E Sussex, England
[4] Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15217 USA
[5] Univ Edinburgh, Astron Inst, Edinburgh EH9 9HJ, Midlothian, Scotland
[6] Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England
[7] Univ Porto, Fac Ciencias, Dept Matemat Aplicada, P-4169007 Oporto, Portugal
[8] Univ Porto, Ctr Astrofis, P-4150762 Oporto, Portugal
[9] Natl Opt Astron Observ, Cerro Tololo Interamer Observ, Tucson, AZ 85719 USA
[10] Univ Portsmouth, Inst Cosmol & Gravitat, Portsmouth PO1 2EG, Hants, England
[11] Univ Hawaii, Dept Phys & Astron, Hilo, HI 96720 USA
[12] Gemini Observ, La Serena, Chile
[13] Univ Nottingham, Nottingham NG9 2RD, England
[14] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[15] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA
[16] CALTECH, Pasadena, CA 91125 USA