1. Department of Physics and Astronomy, Texas Tech University, PO Box 41051, Lubbock, TX 79409, USA
2. Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA
3. School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
5. Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam, the Netherlands
6. Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain
7. Department of Earth, Atmospheric, and Planetary Sciences, M.I.T., Cambridge, MA 02139, USA