1. NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771, USA
2. Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250, USA
3. Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
4. Max-Planck-Institut für extraterrestrische Physik, Gießenbachstraße 1, D-85748 Garching, Germany
5. Department of Astronomy and Center for Space Science and Technology (CRESST), University of Maryland, College Park, MD 20742-2421, USA
6. Dr. Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Sternwartstr. 7, D-96049 Bamberg, Germany
7. Physics Department and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion, Crete, Greece
8. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
9. Institute of Astrophysics, Foundation for Research and Technology-Hellas, GR-71110 Heraklion, Greece