1. Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218, USA
2. Universidade Federal de Santa Maria, CCNE, Departamento de Física, 97105-900 Santa Maria, RS, Brazil
3. New York City Council, New York, USA
4. Center for Astrophysics and Space Sciences, University of California San Diego, 9500 Gilman Drive La Jolla, CA 92093, USA
5. Department of Physics and Astronomy, University of California, Riverside, CA 92507, USA
6. Department of Physics, Rhodes College, Memphis, TN 38112, USA
7. Instituto de Fisica – UFRGS Campus do Vale, CP 15051, 91501-970 Porto Alegre, RS, Brasil
8. Department of Astronomy, University of Maryland, Physical Sciences Complex, Stadium Drive, College Park, MD 20742-2421, USA
9. Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
10. Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101, USA
11. Zentrum für Astronomie der Universität Heidelberg Astronomisches Rechen-Institut, M”onchhofstr, D-12-14 69120 Heidelberg, Germany