1. CIERA and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
2. Department of Astronomy and Theoretical Astrophysics Center, University of California Berkeley, Berkeley, CA 94720, USA
3. TAPIR, Mailcode 350-17, California Institute of Technology, Pasadena, CA 91125, USA
4. Institute for Computational Science, University of Zurich, Zurich, CH-8057, Switzerland
5. Department of Physics, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
6. The Observatories of the Carnegie Institution for Science, Pasadena, CA 91101, USA
7. Department of Physics, University of California, Davis, CA 95616, USA
8. Department of Physics, CASS, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA