[1] Univ Canterbury, Dept Phys & Astron, Christchurch, New Zealand
[2] Space Telescope Sci Inst, Baltimore, MD 21218 USA
[3] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA
[4] CNRS, INSU, Inst Astrophys Paris, F-75014 Paris, France
[5] S African Astron Observ, ZA-7935 Cape Town, South Africa
[6] Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands
[7] Inst Adv Study, Princeton, NJ 08540 USA
[8] Univ Tasmania, Dept Phys, Hobart, Tas 7001, Australia
[9] Perth Observ, Perth, WA 6076, Australia
[10] Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands