1. Departamento de Física, CCNE, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil
2. Laboratório Interinstitucional de e-Astronomia - LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil
3. Departamento de Física, IF, Universidade Federal do Rio Grande do Sul, CP 15051, 91501-970, Porto Alegre, RS, Brazil
4. Observatório Nacional - MCT, Rua General José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil
5. Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
6. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
7. Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
8. Apache Point Observatory, PO Box 59, Sunspot, NM 88349, USA
9. Sternberg Astronomical Institute, Moscow State University, 119992 Moscow, Russia
10. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309-0389, USA