♦ VLBA ♦ NRAO ♦ VLBA ♦ NRAO ♦ VLBA ♦

o THE NATIONAL RADIO C 70 DESCRIPTION OF THE ARRAY cc ASTRONOMY OBSERVATORY o

radio telescope design exploits new SOCORRO, NEW MEXICO TUCSON, ARIZONA technical innovations in the construction of The large precision steerable antennas, low noise GREEN BANK, WEST VIRGINIA O receivers, high-speed magnetic tape record­ ■=£ 70 cc :> ings, stable atomic frequency standards, and o large fast digital computers. The feasibility of the VLBA concept has already been demon­ The National Radio Astronomy Observatory strated through the development of sophisti­ maintains and operates radio telescopes and cated transcontinental and intercontinental CO their associated instrumentation as research CO long baseline interferometers. facilities for the science of radio astrono­ The VLBA radio telescope will consist of my. The astronomers and students who use ten dedicated and automated 25-meter (82-foot) these telescopes come from many universities, o diameter antennas distributed from Hawaii to research institutions and government labora­ wavelengths, is located on Kitt Peak near At the AOC the magnetic data tapes from each Tucson, Arizona. In 1980, the NRAO dedicated antenna will be correlated in a specially the Very Large Array (VLA) radio telescope, VLBA designed digital computer system which will located 52 miles west of Socorro, New Mexico. be capable of nearly one trillion multiplica­ The VLA is a wye-shaped array of 27 antennas, tions per second. Central computer processing all of which operate together as a single O of the recorded data from all ten antennas interferometric radio telescope designed to - subsequently allows the synthesis of a single provide very precise pictures of radio o radio telescope 8000 kilometers (5000 miles) sources. The central administrative and in diameter, physically the largest dedicated scientific offices of the NRAO are located telescope on Earth. in Charlottesville, Virginia. ^(VNSCO/Vr/^

Annually, nearly 700 visiting scientists use the facilities of the NRAO for their research. This interaction between visiting scientists and Observatory staff provides a continuing vitality which serves as a cata­ lyst for the advancement and evolution of the science of radio astronomy.

FOR FURTHER INFORMATION, CONTACT: National Radio Astronomy Observatory Edgemont Road THE NATIONAL RADIO ASTRONOMY OBSERVATORY Charlottesville, VA 22903-2475 USA OPERATED BY ASSOCIATED UNIVERSITIES, INC. BIS Telephone: (804) 296-0211 UNDER CONTRACT WITH THE NATIONAL SCIENCE FOUNDATION THE VERY LONG BASELINE ARRAY (VLBA) RADIO TELESCOPE

The VLBA is a stunning technological leap.

The Very Long Baseline Array (VLBA) radio telescope is one of the great technological breakthroughs of modern science and engineering. Its unparalleled scientific productivity will have profound implications for our understanding of the universe and its contents.

OBSERVING STAR BIRTH THE RADIO GALAXY 3C 120 LOOKING INTO THE HEART AND STAR DEATH OF GALAXIES AND QUASARS

Astronomers will probe deeply into gaseous The VLBA will have an unrivaled capability clouds where stars are being born. Observations for sensing motion and fine detail within the of radio signals from molecules in cocoons hearts of distant galaxies and quasars. Vivid light years surrounding the youngest stars will reveal insight will be gained into the nature of the details of the mysterious process of stellar incredible and mysterious violence tearing ga­ birth. laxies and quasars apart. Radio interferometers, using very long base­ Some stars die violently in awesome supernova lines, have already observed a staggering explosions. The VLBA will be able to perceive The VLBA will unveil phenomenon in distant radio sources. Violent star death in distant galaxies with unparalleled events at the center of quasars and radio clarity. details within the aore of galaxies eject blobs of radiating matter at ap­ 2C 120 with parent speeds greater than that of light. photographic The VLBA will give a detailed perspective of clarity. this violent activity so that radio 'photographs' MEASUREMENT OF and even radio 'movies' of these objects can be made. The true nature of the motions in and CONTINENTAL DRIFT around the central engine powering the awesome phenomenon of the quasar will be studied. The VLBA can measure astronomical positions to an incredible accuracy — a fraction of a milliarcsecond. This allows the location of the individual antennas in the array to be pinpointed THE SIZE OF THE UNIVERSE to about one centimeter. Direct measurement of the distance to objects Such information will lead to the direct throughout our Galaxy as well as in nearby determination of continental drift, the earth's galaxies, something which is extremely difficult rate of rotation, and the wobble of its axis. to do by other means, is made possible by the Even the effect of wind on the rotation of the VLBA. These data will allow the size and age of earth will be detectable with the VLBA. light years the universe to be more accurately determined.

INTERNATIONAL COOPERATION

The VLBA project is national, and potentially international, in scope. Radio astronomers from many different institutions across the United States are involved in the design and construction process. Astronomers from all over the world will be able to use the facility. Very Long Baseline Interferometry (VLBI) is an international science. U.S. scientists have long been leaders in the field and have helped pioneer the development of facilities throughout the world. The construction of the VLBA will assure the United States a leadership position for decades to come. International participation will ensure full exploitation of this remarkable radio telescope. Antennas in other nations on five continents can be linked to the VLBA to form the largest radio telescope that can ever be spread over the planet. In the future it will be possible to link the VLBA to antennas in space, thus extending its capabilities even further.