[1] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England
[2] Swinburne Univ, Hawthorn, Vic 3122, Australia
[3] ESO, D-85748 Garching, Germany
[4] Carnegie Observ, Pasadena, CA 91101 USA
[5] European So Observ, Santiago 19, Chile
[6] Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA
[7] STScl, Baltimore, MD 21218 USA
[8] Univ Oregon, Dept Phys, Eugene, OR 97402 USA