1. Departamento de Astronomia, Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, R.S., Brazil
2. Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciencias Atmosfericas da USP, Cidade Universitaria, CEP:05508900, Sao Paulo, SP, Brazil
3. Centre for Astrophysics & Supercomputing, Swinburne University, Hawthorn VIC 3122, Australia
4. Department of Physics and Astronomy, San José State University, San Jose, CA 95192, USA
5. University of California Observatories, 1156 High St., Santa Cruz, CA 95064, USA
6. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen, Germany
7. School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK