1. Department of Particle Physics and Astrophysics, Weizmann Institute of Science , 76100 Rehovot , Israel
2. School of Physics and Astronomy, Tel Aviv University , Tel Aviv 69978 , Israel
3. Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125 , USA
4. Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125 , USA
5. IPAC , California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 , USA
6. Cahill Center for Astronomy and Astrophysics, California Institute of Technology , Pasadena, CA 91125 , USA
7. School of Physics and Astronomy, University of Minnesota , Minneapolis, MN 55455 , USA