This story continues from Galactic archaeology— digging into the Milky Way’s past

But already, another Australian-led innovation in astronomical instrumentation is providing researchers with the critical information they need to understand the motions of stars within different parts of our galaxy, such as its main body, the bulging core, and the extended halo that surrounds it. Researchers are also searching for evidence of galactic cannibalism—swarms of stars that could be remnants of dwarf galaxies consumed by the Milky Way.

The innovation, called the 6dF instrument, is being used by a multinational consortium, the RAdial Velocity Experiment (RAVE), to measure the radial velocities of more than half a million stars. It is mounted on the Australian National University’s UK Schmidt Telescope at Siding Spring in New South Wales. Radial velocity is movement toward or away from the observer along the light of sight, as distinct from motion across the line of sight. The survey, which began in 2003, will be completed in 2011.

“Using 6dF’s robotic fibre optics system, we can measure about 100 stars at once and quickly build up a very large database,” says Fred Watson from the Australian Astronomical Observatory, who manages the RAVE project.

RAVE has also recorded the spectra of all its target stars, enabling the astronomers to fingerprint them chemically, providing information vital for understanding stellar evolution.

“These fingerprints are already giving us insights into the way our galaxy has developed over its 12-billion-year history,” Fred says.

PHOTO: RAVE PROJECT MANAGER, FRED WATSON, WITH THE UK SCHMIDT TELESCOPE. CREDIT: SHAUN AMY.

Australian Astronomical Observatory, New South Wales
Professor Fred Watson, Tel: +61 (2) 6842 6301, fgw@aao.gov.au, www.aao.gov.au and www.rave-survey.aip.de/rave/