¹ Princeton University Observatory, Peyton Hall, Princeton, NJ 08544
² Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059
³ Department of Astronomy, MS105-24, California Institute of Technology, 1201 East California Boulevard, Pasadena, CA 91125
⁴ Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218
⁵ Department of Physics, Eötvös University, Budapest, Pf. 32, Hungary, H-1518
⁶ University of Chicago, Astronomy and Astrophysics Center, 5640 South Ellis Avenue, Chicago, IL 60637
⁷ Department of Astronomy and Research Center for the Early Universe, School of Science, University of Tokyo, Hongo, Bunkyo, Tokyo, 113-0033 Japan
⁸ Institute for Cosmic Ray Research, University of Tokyo, 3-2-1 Midori, Tanashi, Tokyo, 188-8502 Japan
⁹ Institute for Advanced Study, Olden Lane, Princeton, NJ 08540
¹⁰ US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420
¹¹ Astronomical Institute, Tohoku University, Aoba, Sendai, 980-8578 Japan
¹² Department of Physics, University of Michigan, 500 East University, Ann Arbor, MI 48109
¹³ Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802