[1] INAF Osservatorio Roma, I-00040 Monte Porzio Catone, Italy
[2] Space Telescope Sci Inst, Baltimore, MD 21218 USA
[3] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[4] Univ Calif Santa Cruz, Dept Astron & Astrophys, UCO Lick Observ, Santa Cruz, CA 95064 USA
[5] Los Alamos Natl Lab, Los Alamos, NM USA
[6] Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA
[7] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA
[8] Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA
[9] Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA
[10] Colby Coll, Dept Phys & Astron, Waterville, ME 04901 USA
[11] Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England
[12] Univ Calif Irvine, Dept Phys & Astron, Irvine, CA USA
[13] Natl Opt Astron Observ, Tucson, AZ 85726 USA
[14] Univ Edinburgh, Royal Observ, Inst Astron, Edinburgh, Midlothian, Scotland
[15] Natl Taiwan Normal Univ, Taipei, Taiwan
[16] NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Observat Cosmol Lab, Greenbelt, MD 20771 USA
[17] Observ Carnegie Inst Sci, Pasadena, CA USA
[18] Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA
[19] Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead, Merseyside, England
[20] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA
[21] Max Planck Inst Extraterr Phys, D-85741 Garching, Germany