[1] Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85748 Garching, Germany
[2] Flatiron Inst, Ctr Computat Astrophys, 162 5th Ave, New York, NY 10010 USA
[3] Univ Sussex, Ctr Astron, Brighton BN1 9QH, E Sussex, England
[4] Univ Helsinki, Dept Phys, Gustaf Hallstromin Katu 2, FI-00014 Helsinki, Finland
[5] Univ Cologne, Phys Inst, Zulpicher Str 77, D-50937 Cologne, Germany