A new and uniquely powerful tool for cutting-edge science is emerging on the crisp, high desert of western New Mexico. Outwardly, it looks much the same as the famed Very Large Array (VLA), a radio telescope that has spent more than three decades on the frontiers of astronomical research. The 27 white, 230-ton dish antennas still peer skyward, the 72 miles of railroad track still wait to transport the antennas across the arid plains, the familiar buildings remain, and crews still fan out across the desert to service the antennas.
Functionally, however, everything has changed. The VLA has become the Expanded VLA (EVLA).
"We have a completely new scientific instrument, with completely new capabilities, and it's enabling research that was impossible until now," said Chris Carilli, Chief Scientist of the National Radio Astronomy Observatory (NRAO). Carilli and Rick Perley, EVLA Project Scientist, outlined the capabilities and early accomplishments of the EVLA at the American Astronomical Society's meeting in Boston, MA.
Carilli presented highlights of projects in which researchers from around the world made first use of some of the EVLA's new capabilities while those capabilities still are being tested. The EVLA already is providing new and tantalizing insights on a wide range of objects from our nearby cosmic neighborhood to the far reaches of the distant Universe.
These new discoveries, and others, will be published in an upcoming special issue of the Astrophysical Journal Letters.
"When the original VLA was dedicated in 1980, it made possible entirely new types of research. Now, as we bring the EVLA on-line, it, too, is revolutionizing our ability to study the Universe," Perley said.
Construction on the EVLA project began in 2001, and completion is scheduled for next year. The project replaced the 1970s-vintage electronic equipment, analog data-transmission system, and the central, special-purpose computing "heart" of the system with state-of-the-art electronics, an all-digital, high-bandwidth data-transmission system, and a new, superfast central supercomputer with an innovative design that revolutionizes scientists' ability to optimize their observations and exquisitely analyze their results.
The new system is more than ten times more sensitive to faint radio emissions from distant astronomical objects than the pre-EVLA system, and covers more than three times more radio frequencies. The EVLA receiving systems would be capable of detecting the weak radio signal from a cell phone at the distance of Jupiter, a half-billion miles away.
The original VLA was authorized by Congress in 1972, and astronomers began using it for research even before its completion. To date, more than 2,500 scientists from around the world have used the VLA for more than 13,000 observing projects. More than 200 Ph.D dissertations have been based on data obtained from VLA observations.
The EVLA project costs $97.99 million in U.S. dollars -- $58.98 million in new direct funding from the National Science Foundation, $1.75 million from Mexico, $17.1 million from Canada in the form of the new central supercomputer, called a correlator, and $20.16 million in the form of labor from existing staff at the NRAO. The current value of the VLA infrastructure on which the EVLA was built is estimated at more than $300 million.
"These early results are only the beginning of a very rich scientific harvest that the EVLA will produce. This new research facility will have a major impact on the most important questions facing astronomers in the 21st Century," said NRAO Director Fred K.Y. Lo.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
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