1. Astrophysics Group, Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
2. Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK.
3. Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA.
5. Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706, USA.
6. Steward Observatory, University of Arizona, Tucson, AZ 85721, USA.
7. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany.
8. Astrophysics Group, Lennard-Jones Laboratories, Keele University, ST5 5BG, UK.
9. European Southern Observatory, Karl Schwarschild Straße 2, D-85748 Garching bei München, Germany.
10. Louisiana State University, Department of Physics and Astronomy, 233-A Nicholson Hall, Tower Drive, Baton Rouge, LA 70803–4001, USA.
11. Department of Astronomy, The Oskar Klein Centre, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
12. Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8583, Japan.
13. Commissariat à l’Energie Atomique et aux Energies Alternatives, Laboratoire Astrophysique, Instrumentation et Modélisation, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette, France.