1. University of Iowa, Department of Physics & Astronomy, 210 Van Allen Hall, Iowa City, Iowa 52242, United States
2. MPI für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching, Germany
3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, United States
4. Cosine Science & Computing BV, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands
5. Cosine Research BV, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands