Support for the Radial Velocity Experiment

Since April 2003 an ambitious survey of the Milky Way has been gathering pace at Siding Spring. Initially the survey used only bright time on the UK Schmidt, but now it has exclusive use of the Schmidt and the 6dF instrument, so its rate of taking spectra has increased to ~140,000 per year. The plan is to obtain spectra for ~million stars, including nearly all accessible stars the ACT-reference catalogue, which has accurate proper motions and space-based photometry for about a million stars. The spectra yield radial velocities accurate to better than 2km/s, estimates of [Fe/H] and [alpha/H], and also good photometric distances. Hence programme stars can be assigned to populations and given all six phase-space coordinates. These data will enable us to carry out a large part of the core science programme of the GAIA mission up to a decade before the GAIA catalogue comes out. Although several UK astronomers are founder members of this survey, PPARC has yet to contribute to its cost. This proposal is for a contribution of order 20% to the costs over 2006 - 2008.