[1] Australia Telescope Natl Facil, Commonwealth Sci & Ind Res Org CSIRO Astron & Spa, POB 76, Epping, NSW 1710, Australia
[2] Curtin Univ, Int Ctr Radio Astron Res, Bentley, WA 6102, Australia
[3] Swinburne Univ Technol, Ctr Astrophys & Supercomp, Hawthorn, Vic 3122, Australia
[4] Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England
[5] Monash Univ, Monash Ctr Astrophys, Sch Phys & Astron, Clayton, Vic 3800, Australia
[6] Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA
[7] Natl Radio Astron Observ, Array Operat Ctr, Socorro, NM 87801 USA
[8] Peking Univ, Sch Phys, Dept Astron, Beijing 100871, Peoples R China
[9] Univ Manchester, Ctr Astrophys, Jodrell Bank, Manchester M13 9PL, Lancs, England
[10] Univ Bielefeld, Dept Phys, D-33615 Bielefeld, Germany
[11] Max Planck Inst Radioastron, D-53121 Bonn, Germany
[12] Chinese Acad Sci, Xinjiang Astron Observ, Urumqi 830011, Xinjiang, Peoples R China
[13] Univ Western Australia, Sch Phys, Crawley, WA 6009, Australia
[14] Univ Melbourne, Sch Phys, Parkville, Vic 3010, Australia