[1] CALTECH, Pasadena, CA 91125 USA
[2] Johns Hopkins Univ, Baltimore, MD 21218 USA
[3] Space Telescope Sci Inst, Baltimore, MD 21218 USA
[4] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[5] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA
[6] Australian Natl Univ, Res Sch Astron & Astrophys, Inst Adv Studies, Weston, ACT 2611, Australia
[7] Natl Opt Astron Observ, Kitt Peak Natl Observ, Tucson, AZ 85726 USA
[8] Carnegie Observ, Pasadena, CA 91101 USA
[9] Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada
[10] NASA, IPAC, Extragalact Database, Pasadena, CA 91125 USA
[11] CALTECH, Pasadena, CA 91125 USA
[12] Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA
[13] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA
[14] Royal Greenwich Observ, Cambridge CB3 0HA, England
[15] Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA