1. Areté Associates , 3194 N Swan Rd, Tucson, AZ 85712, USA
2. Astrophysics Research Institute, Liverpool John Moores University , IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
3. Max-Planck Institut für Astrophysik , Karl-Schwarzschild-Str 1, D-85741 Garching, Germany
4. Leibniz Supercomputing Centre (LRZ) , Boltzmannstr. 1, D-85748 Garching, Germany