THE
ATACAMA LARGE MILLIMETER ARRAY
The
Atacama Large Millimeter Array (ALMA), one of the largest ground-based
astronomy projects of the next decade, is a major new facility for world astronomy.
ALMA will be comprised of a giant array of 12-m submillimetre quality antennas,
with baselines of several kilometres. An additional, compact array of 7-m and
12-m antennas is also foreseen. Construction of ALMA started in 2003 and will
be completed in 2010. The ALMA project is an international collaboration between
Europe, Japan and North America in cooperation with the Republic of Chile.
The
Atacama Large Millimeter Array, or ALMA, is an international collaboration to
develop a world-class telescope array to study the universe from a site in the
foothills of Chile's Andes Mountains. Each of ALMA's antenna dishes will measure
12 m wide. The ALMA antennas will be movable. At its largest, the array will measure
14 km, and at its smallest, only 150 m. Its receivers will cover the range from
30 to 950 GHz. The ALMA correlator, a specialized computer that combines the information
received by the antennas, will perform an astounding 16,000 million-million (1.6x1016)
operations per second. An additional, compact array of 7-m and 12-m antennas is
also foreseen. Construction of ALMA started in 2003 and will be completed in 2012;
it will become incrementally operational from 2010 on.
The
ALMA project is a partnership between Europe, Japan and North America in cooperation
with the Republic of Chile. ALMA is funded in Europe by ESO, in Japan by the National
Institutes of Natural Sciences in cooperation with the Academia Sinica in Taiwan
and in North America by the U.S. National Science Foundation in cooperation with
the National Research Council of Canada. ALMA construction and operations are
led on behalf of Europe by ESO, on behalf of Japan by the National Astronomical
Observatory of Japan and on behalf of North America by the National Radio Astronomy
Observatory, which is managed by Associated Universities, Inc.
ALMA
is located on the high-altitude Llano de Chajnantor (5000
m elevation), east of the village of San Pedro de Atacama in Chile.
The land has been given in concession to CONICYT (The Chilean National Commission
for Science and Technology) by the "Ministerio de Bienes Nacionales"
(Ministry of National Assets). It has also been declared a national reserve for
science because of its unique capabilities for astronomical research. ALMA's location
in the Atacama Desert is one of the highest, driest places on Earth, making it
ideal for astronomical research at millimetre wavelengths, which are absorbed
by atmospheric moisture. When completed (in 2011), ALMA will be the largest and
most capable imaging array of telescopes in the world.
ALMA
will be the largest ground-based astronomy project of the next decade after VLT/VLTI,
and, together with the James Webb Space Telescope (JWST), one of the two major
new facilities for world astronomy possibly coming into operation by the end of
the next decade.
The
comprehensive description of the exciting science that can be done with ALMA was
presented in the article "The Atacama Large Millimeter Array" in the
March 2002 Issue of ESO Messenger. ALMA will detect and study the earliest and
most distant galaxies, the epoch of the first light in the Universe. It will also
look deep into the dust-obscured regions where stars are born to examine the details
of star and planet formation. In addition to these two main science drivers the
array will make major contributions to virtually all fields of astronomical research.
For observations
at millimetre and submillimetre wavelenghts to be possible the atmosphere above
the telescope must be transparent. This requires a site that is high and dry,
and a high plateau in the Atacama Desert of Chile, probably the world's driest,
is ideal - the next best thing to outer space for these observations.
What
it's going to look like when it's finished.