1. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
2. Department of Physics & Astronomy, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9L 0G2, Canada
3. Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904, USA
4. California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
5. Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
6. Department of Astronomy, Columbia University, Mail Code 5246, 550 West 120th Street, New York, NY 10027, USA
7. Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611, USA