ALMA is the largest ground-based astronomy project in existence, and will comprise a giant array of 12-metre submillimetre quality antennas, with baselines of up to about 16 kilometres. An additional, compact array of 7-metre and 12-metre antennas will complement the main array. The ALMA project is an international collaboration between Europe, East Asia and North America in cooperation with the Republic of Chile. ESO is the European partner in ALMA.
ALMA, the Atacama Large Millimetre/submillimetre Array in the Atacama desert of northern Chile, is an astronomical interferometer of radio telescopes. ALMA is an international facility, comprising partners from Europe, Taiwan, Japan, Chile and North America.
The Andean site was chosen due to its favourable climatic conditions. Its high altitude means that at ALMA’s operating wavelengths of 0.3–9.6 mm, the dry atmosphere will be largely transparent. ALMA’s 64 individual 12-m moveable antennae with baselines from 0.15–18 km will provide unprecedented sensitivity, resolution and frequency-coverage at these wavelengths. The typical achievable spatial resolution of 10 milliarcsec is 10 times better than that available with the Very Large Array or Hubble Space Telescope.
In being primed for the detection of cosmic emission in the submillimetre regime, ALMA will be sensitive to the cool Universe. This includes emission from dust and molecules in galaxies at high redshift, from molecular gas at the centre of the Milky Way, from molecular gas in star-forming regions and from molecules and dust in evolved stars.