1Leiden Observatory, Leiden University, Postbus 9513, 2300 RA, Leiden, The Netherlands 2Deutsches Elektronen Synchrotron DESY, Platanenallee 6, D-15738 Zeuthen, Germany 3Institut für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin, Germany 4Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA 5Space Research Institute, Russian Academy of Sciences, Profsoyuznaya ul. 84/32, Moscow, 117997, Russia 6Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany 7Department of Astronomy and Space Science, Chungbuk National University, Cheongju 361-763, Republic of Korea 8Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA02138, USA 9Cahill Center for Astrophysics, California Institute of Technology, MC 249-17, 1200 E California Boulevard, Pasadena, CA 91125 10Fakultät für Physik & Astronomie, Ruhr-Universität Bochum, D-44780 Bochum, Germany 11Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA 12Department of Astronomy, University of Maryland, College Park, MD 20742, USA 13Caltech Optical Observatories, California Institute of Technology, Pasadena, CA 91125, USA 14The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691, Stockholm, Sweden 15DIRAC Institute, Department of Astronomy, University of Washington, 3910 15th Avenue NE, Seattle, WA 98195, USA 16IPAC, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA