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Star performer: the Atacama Large Millimeter Array would study the formation of distant galaxies.

Astronomers around the world are gearing up to fight to secure funds for a large array telescope in the Andes that would help them study how galaxies are formed.

Such an instrument has been a top astronomy priority for years, and on 6 April research-agency representatives from Japan, North America and Europe met in Tokyo but promised only to try to reach agreement on its construction.

Funding for the Atacama Large Millimeter Array (ALMA) is not yet assured — particularly in the United States, which is supposed to pay about one third of its $660 million construction costs.

The Bush administration's first budget proposal, issued in February, allowed no money for ALMA from the National Science Foundation (NSF), which funds ground-based astronomy in the United States.

The NSF had planned to start construction in 2002, using money it had meant to spend on the smaller Millimeter Array, a US project which was subsumed into ALMA. ALMA also absorbed Europe's Large Southern Array proposal and a Japanese project, the Large Millimeter and Submillimeter Array.

ALMA would be located on the Andean plateau in Chile, where the dry atmosphere will allow short-wavelength signals to reach the telescope. The most distant galaxies can be observed as they were when they first formed because it takes so long for their light to reach Earth. Dust around young stars blocks out most of the visible light in these galaxies, but the millimetre and submillimetre radiation shines through.

“It means that you can make very detailed images of galaxies and stars in formation,” says Bob Brown, deputy director of the National Radio Astronomy Observatory, which oversees the US contribution to ALMA.

ALMA's 64 12-metre dishes would simulate a dish of up to 14 kilometres across. Integrating the 64 signals would provide a resolution ten times better than that of the Hubble Space Telescope. As well as resolving very distant galaxies, ALMA should be able to detect planets in our own galaxy.

Funding for ALMA in 2002 is likely to be approved in Europe and Japan, but astronomers face an uphill battle in the United States. A panel of scientists has advised the NSF that construction should proceed next year.

US researchers are preparing to take their case to Congress, which will consider the Bush proposal and develop a final 2002 budget by October. The Senate has indicated that it would like to give more money to the NSF than Bush proposed (see page 731).

Canada is expected to decide on a US$30 million contribution later this month, says Ralph Pudritz, an astronomer at McMaster University in Hamilton, Ontario. Pudritz adds that no single country's contribution will be absolutely critical in 2002. “As long as the taps have started to turn on at some significant level, construction can begin,” he claims.