1. Universidade de São Paulo, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Departamento de Astronomia, São Paulo, SP 05508-090, Brazil
2. Eureka Scientific, Inc., 2452 Delmer Street Suite 100, Oakland, CA 94602-3017, USA
3. Department of Physics and Astronomy, Minnesota State University, Mankato, MN 56001, USA
4. School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
5. Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487, USA