1. South African Astronomical Observatory, PO Box 9, Observatory, 7935, South Africa and Centre for Space Research, North-West University, Potchefstroom 2520, South Africa
2. Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, Macul, Casilla 306, Santiago 22, Chile
3. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Science, UCB-389, University of Colorado, Boulder, CO 80309, USA
4. Department of Astronomy and Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8, Canada
5. Departamento de Ciencias Fisicas, Universidad Andres Bello, Fernandez Concha 700, Las Condes, Santiago, Chile
6. Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL, 60637, USA
7. Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, ON, M3J 1P3, Canada
8. Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506, USA
9. Zentrum für Astronomie, Institut für Theoretische Astrophysik Philosophenweg 12, D-69120 Heidelberg, Germany
10. Leiden Observatory, Leiden University, P. O. Box 9513, NL-2300 RA Leiden, The Netherlands
11. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA
12. Australian Astronomical Observatory, North Ryde, NSW 2113, Australia
13. Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan