¹ Division of Physics, Mathematics and Astronomy, California Institute of Technology, MS 105-24, Pasadena, CA 91125
² Space Radiation Laboratory, California Institute of Technology, MS 220-47, Pasadena, CA 91125
³ INAF, Osservatorio Astronomica di Brera, via E. Bianchi 46, I-23807 Merate (LC), Italy
⁴ Department of Astronomy, University of California, Berkeley, CA 94720
⁵ Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064
⁶ NASA Goddard Space Flight Center, Greenbelt, MD 20771
⁷ CRESST and Astroparticle Physics Laboratory, NASA/GSFC, Greenbelt, MD 20771
⁸ Universities Space Research Association, 10211 Wincopin Circle, Suite 500, Columbia, MD 21044
⁹ Department of Astronomy, University of Maryland, College Park, MD 20742
¹⁰ University of Virginia, P.O. Box 400325, Charlottesville, VA 22903
¹¹ National Radio Astronomy Observatory, Socorro, NM 87801
¹² Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802
¹³ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822
¹⁴ Observatories of the Carnegie Institute of Washington, Pasadena, CA 91101
¹⁵ Princeton University Observatory, Princeton, NJ 08544
¹⁶ Space Research Institute, Profsoyuznaya 84/32, 117997 Moscow, Russia
¹⁷ Max-Plank-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, D-85741 Garching, Germany