ALMA Achieves Major Milestone With Antenna-Link Success (Forwarded)

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March 7, 2007

ALMA Achieves Major Milestone With Antenna-Link Success

The Atacama Large Millimeter/submillimeter Array (ALMA), an international
telescope project, reached a major milestone on March 2, when two ALMA
prototype antennas were first linked together as an integrated system to
observe an astronomical object.

The milestone achievement, technically termed "First Fringes," came at the
ALMA Test Facility (ATF) on the grounds of the National Radio Astronomy
Observatory's (NRAO) Very Large Array (VLA) radio telescope in New Mexico.
NRAO is a facility of the National Science Foundation (NSF), managed by
Associated Universities, Incorporated (AUI). AUI also is designated by NSF
as the North American Executive for ALMA.

Faint radio waves emitted by the planet Saturn were collected by the two
ALMA antennas, then processed by new, state-of-the-art electronics to turn
the two antennas into a single, high-resolution telescope system, called
an interferometer.

Such pairs of antennas are the basic building blocks of multi-antenna
imaging systems such as ALMA and the VLA. In such a system, each antenna
is combined electronically with every other antenna to form a multitude of
pairs. Each pair contributes unique information that is used to build a
highly-detailed image of the astronomical object under observation. When
completed in 2012, ALMA will have 66 antennas.

The successful Saturn observation began at 7:13 p.m., U.S. Mountain Time
Friday (0213 UTC Saturday). The planet's radio emissions at a frequency of
104 GigaHertz (GHz) were tracked by the ALMA system for more than an hour.

"Our congratulations go to the dedicated team of scientists, engineers and
technicians who produced this groundbreaking achievement for ALMA. Much
hard work and many long hours went into this effort, and we appreciate it
all. This team should be very proud today," said NRAO Director Fred K.Y.
Lo. "With this milestone behind us, we now can proceed with increased
confidence toward completing ALMA," he added.

ALMA, now under construction at an elevation of 16,500 feet in the Atacama
Desert of northern Chile, will provide astronomers with the world's most
advanced tool for exploring the Universe at millimeter and submillimeter
wavelengths. ALMA will detect fainter objects and be able to produce much
higher-quality images at these wavelengths than any previous telescope
system. Scientists are eager to use this transformational capability to
study the first stars and galaxies that formed in the early Universe, to
learn long-sought details about how stars are formed, and will trace the
motion of gas and dust as it whirls toward the surface of newly-formed
stars and planets.

"This was fantastic work. Using our two prototype antennas to observe
Saturn was the first complete, end-to-end test of the advanced systems we
are building for ALMA," said Adrian Russell, North American Project
Manager for ALMA. "ALMA is an extraordinary international endeavor, and
the collaboration of partners from around the world is vital to the
success of the project," Russell added.

"The success of this test is fundamental proof that the hardware and
software now under development for ALMA will work to produce a truly
revolutionary astronomical tool," said Massimo Tarenghi, Director of the
Joint ALMA Office.

"This achievement results from the integration of many state-of-the-art
components from Europe and North America and bodes well for the success of
ALMA in Chile," said Catherine Cesarsky, ESO's Director General.

In addition to the leading-edge electronic and electro-optical hardware
and custom software that proved itself by producing ALMA's first fringes,
the system's antennas are among the most advanced in the world. The
stringent requirements for the antennas included extremely precise
reflecting surfaces, highly accurate ability to point at desired locations
in the sky, and the ability to operate reliably in the harsh,
high-altitude environment of the ALMA site.

The ALMA Test Facility includes prototype antennas built by VertexRSI in
the U.S. and by the AEC Consortium (ALCATEL Space of France and European
Industrial Engineering of Italy). These antennas were evaluated
individually at the ATF. Both prototypes were fitted with electronic
equipment for receiving, digitizing and transmitting signals back to a
central facility. At the ATF, a small-scale prototype version of ALMA's
giant central, special-purpose computer, called a correlator, has been
installed. The correlator combines the signals to make the antennas work
together as a single astronomical instrument. The full-scale ALMA
correlator is being built at the National Radio Astronomy Observatory's
Technology Center in Charlottesville, Virginia, and will be installed at
the high-altitude site in Chile when completed. ALMA also will include
Japanese antennas built by Mitsubishi.

ALMA is an international astronomy facility. It is a partnership of
Europe, Japan, and North America in cooperation with the Republic of
Chile. ALMA is funded in Europe by the European Southern Observatory
(ESO), in Japan by the National Institutes of Natural Sciences (NINS) in
cooperation with the Academia Sinica in Taiwan, and in North America by
the U.S. National Science Foundation (NSF) in cooperation with the
National Research Council of Canada (NRC). ALMA construction and
operations are led on behalf of Europe by ESO, on behalf of Japan by the
National Astronomical Observatory of Japan (NAOJ) and on behalf of North
America by the National Radio Astronomy Observatory (NRAO), which is
managed by Associated Universities, Inc. (AUI).

Photos and graphics,
http://www.nrao.edu/pr/2007/almafringes/graphics.shtml


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