1. Institute for Computational Science, University of Zurich , Wintherthurerstrasse 190, CH-8057 Zürich, Switzerland
2. Max-Planck-Institute for Astrophysics , Karl-Schwartzschild-Strasse 1, D-85748 Garching, Germany
3. Anton Pannekoek Institute for Astronomy, Universiteit van Amsterdam , Science Park 904, NL-1098 XH Amsterdam, the Netherlands
4. ETH Zurich / Swiss National Supercomputing Centre (CSCS) , Via Trevano 131, CH-6900 Lugano, Switzerland
5. Physikalisches Institut der Universität zu Köln , Zülpicher Strasse 77, D-50937 Köln, Germany