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NRAO VLA Home Page: What is the VLA? What is the VLA?

The Very Large Array (VLA) is one of the world's premier astronomical . The VLA consists of 27 antennas arranged in a huge Y pattern up to 36km (22 miles) across -- roughly one and a half times the size of Washington, DC.

Each antenna is 25 meters (81 feet) in diameter; they are combined electronically to give the resolution of an antenna 36km (22 miles) across, with the sensitivity of a dish 130 meters (422 feet) in diameter. More photographs of the VLA History: ❍ 1972 August: approved by Congress ❍ 1973 April: construction started ❍ 1975 September 22: first antenna put in place ❍ 1976 February 18: first fringes ❍ 1981 January: entire array completed nearly one year ahead of schedule! The total cost was $78,578,000 (in 1972 dollars), roughly $1 per tax-payer at the time; the project was completed within the allotted budget.

Location: , west of Socorro, . ❍ latitude = 34 04' 43.497" north ❍ longitude = 107 37' 03.819" west ❍ elevation = 2124 m

http://www.nrao.edu/doc/vla/html/VLAintro.shtml (1 of 3) [5/26/1999 1:22:34 PM] NRAO VLA Home Page: What is the VLA? Size: Each antenna: 25m in diameter, 230 tons. The array: There are four configurations: A array, with a maximum antenna separation of 36km; B array -- 10km; C array -- 3.6km; and D array -- 1km. The are switched between these configurations every four months or so.

Resolution: 0.04arcseconds The resolution of the VLA is set by the size of the array -- up to 36km (22 miles) across. At our highest frequency (43GHz) this gives a resolution of 0.04 arcseconds: sufficient to see a golf ball held by a friend 150km (100 miles) away. Of course, very few golf balls contain high-power radio transmitters...

Misc. antenna information: Slew rates: 40 degrees per minute in azimuth, 20 degrees per minute in elevation Minimum elevation angle: 8 degrees above the horizon

Frequency coverage: The VLA can observe at various bands between 300 and 50,000 MHz (90 to 0.7cm):

Receivers Available at the VLA

C X P Band L Band U Band K Band Q Band Band Band

Frequency 0.30-0.34 1.34-1.73 4.5-5.0 8.0-8.8 14.4-15.4 22-24 40-50 (GHz)

Wavelength 90 20 6 3.6 2 1.3 0.7 (cm)

Primary beam 150 30 9 5.4 3 2 1 (arcmin)

Highest resolution 6.0 1.4 0.4 0.24 0.14 0.08 0.05 (arcsec)

System 150-180.K 37-75.K 44.K 34.K 110.K 160-190.K 90-140.K Temp

http://www.nrao.edu/doc/vla/html/VLAintro.shtml (2 of 3) [5/26/1999 1:22:34 PM] NRAO VLA Home Page: What is the VLA? How does it work? The VLA is an interferometer; this means that it operates by multiplying the data from each pair of telescopes together to form interference patterns. The structure of those interference patterns, and how they change with time as the earth rotates, reflect the structure of radio sources on the sky: we can take these patterns and use a mathematical technique called the Fourier transform to make maps.

Who uses it? The VLA is used primarily by astronomers from around the world. It's also occasionally used for atmospheric/weather studies, satellite tracking, and other miscellaneous science. If you would like to use the VLA for your research experiment, please see the instructions for submitting proposals .

Who runs it? The VLA is operated by the National Radio (NRAO), which is a facility of the National Science Foundation (NSF), operated under cooperative agreement by Associated Universities, Inc. (AUI).

Can I go see it? The VLA is open to the public; follow this link for directions and other information.

Pretty images from the VLA Images from the local website Alan Bridle's beautiful jets

Recent results Recent press releases Highlights of this month's VLA observations

VLA Home Page

Last modified 20 April 1999 [email protected]

http://www.nrao.edu/doc/vla/html/VLAintro.shtml (3 of 3) [5/26/1999 1:22:34 PM] Some Aerial Views of the VLA Some Aerial Views of the VLA

Click on any image for a larger version. All photos are by Dave Finley, courtesy National Observatory and Associated Universities, Inc.

An overall view of the VLA in its closest configuration, looking North-Northeast.

Overall view of the VLA, looking South.

http://www.nrao.edu/intro/vlapix/vlaviews.index.html (1 of 4) [5/26/1999 1:24:59 PM] Some Aerial Views of the VLA

The North Arm of the VLA, looking South toward the center.

The center of the VLA, with the antennas in close configuration.

http://www.nrao.edu/intro/vlapix/vlaviews.index.html (2 of 4) [5/26/1999 1:24:59 PM] Some Aerial Views of the VLA

A close-in look at the center of the VLA.

The VLA, with Tres Montosas in the background.

http://www.nrao.edu/intro/vlapix/vlaviews.index.html (3 of 4) [5/26/1999 1:24:59 PM] Some Aerial Views of the VLA

Twilight on the VLA, looking Southwest.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc..

http://www.nrao.edu/intro/vlapix/vlaviews.index.html (4 of 4) [5/26/1999 1:24:59 PM] NRAO Very Large Array Images

Images from the Very Large Array

● The Extra-galactic Radio Source ( 235k):

● The Remnant Cas A ( 369k):

http://www.nrao.edu/doc/vla/html/VLA-images.shtml (1 of 2) [5/26/1999 1:25:33 PM] NRAO Very Large Array Images ● The Arc at the Galactic Center ( 235k):

Last modified 28 November 1995 [email protected]

http://www.nrao.edu/doc/vla/html/VLA-images.shtml (2 of 2) [5/26/1999 1:25:33 PM] Alan Bridle's Image Gallery Images of Radio Galaxies and

Images on this page are thumbnails, linked to larger (30-80k) versions

Radio Galaxies

| 3C31 | 3C219 | 3C272.1 | 3C288 | 3C353 |

Quasars

| Index & description | | 3C175 | 3C204 | 3C215 | 3C263 | 3C334 | 3C351 |

Images at Other WWW Sites

Go back to:

● Alan Bridle's Home Page ● NRAO Charlottesville Home Page ● NRAO VLA Home Page ● AstroWeb Home Page

HTML 3.2 last updated: 1998 August 25, 14:46 EDT

http://www.cv.nrao.edu/~abridle/images.htm [5/26/1999 1:26:05 PM] NRAO Recent Press Releases

National Radio Astronomy Observatory Recent Press Releases 1999:

● Superfast Cosmic Jet "Hits the Wall" ● Astronomers Discover Rotating Disk Around Young, Massive ● "Movie Star" Acting Strangely, Astronomers Find ● Astronomers Discover Spectacular Structure in Distant Galaxy 1998:

● Nearby Quasars Result From Galactic Encounters, VLA Studies Indicate ● New Mexico Fiber-Optic Link Marks Giant Leap Toward Future of Radio Astronomy ● Astronomers Surprised to Find Elongated Radio-Emitting Region at Center of ● Possible Analog for Early Solar System Disk Found ● Cosmic Flasher Reveals All ● Background Information: Magnetars, Soft Gamma-Ray Repeaters and the Most Powerful Magnetic Fields in the Universe ● VLA Reveals Surprising Pair of Potential Planetary Systems ● VLA Observations Confirm Origin of Gamma Ray Bursts in Short-Lived ● Background Information: Deciphering Gamma Ray Burst Physics With Radio Telescopes ● Strange, Bursting Star System Has Astronomers Scrambling ● VLA Shows "Boiling" in Atmosphere of 1997:

● Radio Observations Provide New Clues to Gamma Ray Fireball ● Astronomers Make First Images With Space Radio

http://www.aoc.nrao.edu/doc/pr/pr.html (1 of 3) [5/26/1999 1:26:20 PM] NRAO Recent Press Releases ● Radio Astronomers Reveal "Bizarre" Behavior of Gamma Ray Burster ● Curved Radio Jet in Center of Nearby Galaxy Complicates Picture of Active Galactic Nuclei ● VLBA Gives Researchers Unprecedented Look at Workings of Distant Star ● Very Large Array Detects Radio Emission from Gamma-Ray Burst ● "Axis of Universe" Not Seen in Data, Astronomers Say ● Launch Will Create a Larger than Earth ● New Observations Deepen Mystery Surrounding Water Masers in Elliptical Galaxy ● "Microquasar" Discoveries Win Prize for Astronomers ● Extraordinary Cosmic Laboratory Helps Unravel Mysteries of a Galaxy's Powerful Central "Engine" 1996:

● New Technologies Promise Dramatic Increase In Capabilities of the Very Large Array ● NRAO 12-Meter Radio Telescope Detects Molecular Emission from Comet Hyakutake ● Middle-School Students to Make Optical Observations During VLA Radar Study of Comet Hyakutake ● Research Teams Will Use Very Large Array To Study Close-Passing Comet ● Detecting Extrasolar With Millimeter-Wave Observatories ● New Galaxies From Old? VLA Observations Strengthen the Case 1995:

● Astronomers Make "Movie" of Radio Images Showing Supernova Explosion ● VLA Will Receive Galileo Probe Signals To Measure Jupiter's Winds ● Emerging Picture of in Double-Star System Promises Exciting Yield of New Physics Data ● VLBA Tracks Ejected Material From Mysterious X-Ray Nova ● Tremendous Mass Concentration in Strange Galaxy Revealed by VLBA 1994:

● Superluminal Motion Found In Milky Way ● NRAO Makes Available VLA Sky Survey Maps For additional information, please contact Dave Finley

http://www.aoc.nrao.edu/doc/pr/pr.html (2 of 3) [5/26/1999 1:26:20 PM] NRAO Recent Press Releases [email protected]

http://www.aoc.nrao.edu/doc/pr/pr.html (3 of 3) [5/26/1999 1:26:20 PM] NRAO Very Large Array Home Page NRAO Very Large Array

What is the VLA? What's New at the VLA?

● Important notices and announcements ● Current and upcoming configurations ● Proposal deadlines ● Current schedule, newsletter, test minutes, memos, and software ● Press releases The VLA Expansion Project Contact People Using the VLA

● Asking for time ● Preparing for observations ● Phase Monitor ● Visiting the VLA ● After the observations ● Publications Documentation Software

http://www.nrao.edu/doc/vla/html/VLAhome.shtml (1 of 2) [5/26/1999 1:27:33 PM] NRAO Very Large Array Home Page Special Topics and Observing Modes

● Calibration ● Radio frequency interference (RFI) ● Observing bands (7mm, 90cm, 4m) ● Observing modes (spectral line, polarization, high dynamic range imaging, astrometry, mosaicing, ) ● VLBI at the VLA Past Observations

● Pretty images ● Schedules ● Configurations ● Observing logs ● Baseline corrections ● Archival information Staff Information

Socorro Home Page

Last modified 22 February 1999 [email protected]

http://www.nrao.edu/doc/vla/html/VLAhome.shtml (2 of 2) [5/26/1999 1:27:33 PM] VLA Current Observations Highlights of Current VLA Observations

1 - 31 May 1999

Protogalaxies in the Dark Ages

On seven different days this month, scientists will use the VLA to study the third most-distant yet found, at a distance of more than 12 billion light-years. They are studying radio emission that indicates the presence of heavy elements in this object when the universe was very young. At such great distances, astronomers believe we see the young universe during its "dark ages," as the first stars were being formed. The existence of the heavy elements Carbon and Oxygen indicates, however, that some stars already had lived through their life cycles even at that early age of the universe. A second team of observers will seek to find these heavy elements in even more distant (and thus younger) protogalaxies. Colliding Galaxies

A team of astronomers will study several sets of galaxies that are colliding with each other. This study, which uses optical and infrared telescopes in addtion to the VLA, seeks to learn what role collisions play in the formation of some types of galaxies. Magnetic Fields on the

Three teams of solar specialists will study the sun this month. Their observations will seek to learn about flaring loops on the sun and about the magnetic fields and heating in the sun's outer atmosphere, called the corona. The Galactic Center

Two observing teams will study the center of our own Galaxy, the Milky Way. One will use a new system to observe the Galaxy's central region at low frequency (74 MHz) to seek to find new structures not previously seen. The other team will try to learn about motions of features near the center. Gamma-ray Bursts

The VLA will be used by astronomers looking for radio emission from the "fireballs" presumed to result from the explosions that cause cosmic bursts of Gamma rays. In May 1997, the VLA made the first-ever detection of radio waves coming from a gamma-ray burster, and measured the emission from that object

http://www.nrao.edu/doc/vla/html/VLAcurrobs.shtml (1 of 2) [5/26/1999 1:28:39 PM] VLA Current Observations for months afterward. As satellites with gamma-ray detectors continue to give rapid notice of these bursts, the VLA, along with other ground-based observatories, will seek to detect the object at wavelengths longer than those of gamma rays. The VLA also detected radio emission from Gamma Ray Bursters that exploded on March 29, 1998. July 3, 1998, and January 23, 1999.

VLA Home Page

Last modified 30 April 1999 [email protected]

http://www.nrao.edu/doc/vla/html/VLAcurrobs.shtml (2 of 2) [5/26/1999 1:28:39 PM]