1. Department of Particle Physics and Astrophysics, Weizmann Institute of Science , 76100 Rehovot , Israel
2. Department of Physics Core Facilities, Weizmann Institute of Science , Herzl St 234, Rehovot 7610001 , Israel
3. Department of Astronomy and Astrophysics, University of Toronto , Toronto M5R 0A3, ON , Canada
4. Racah Institute of Physics, The Hebrew University , Jerusalem 91904 , Israel
5. Astrophysics Science Division, NASA Goddard Space Flight Center , MC 661, Greenbelt, MD 20771 , USA
6. Joint Space-Science Institute, University of Maryland , College Park, MD 20742 , USA