[1] Univ Bonn, Sternwarte, D-53121 Bonn, Germany
[2] Weizmann Inst Sci, Fac Phys, IL-76100 Rehovot, Israel
[3] Leiden Observ, NL-2300 RA Leiden, Netherlands
[4] Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1012 WX Amsterdam, Netherlands
[5] Univ Amsterdam, Sect Computat Sci, NL-1012 WX Amsterdam, Netherlands
[6] Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan