what is the vla?btc.montana.edu/ceres/malcolm/cd/universe/assets/multimedia/vlaintro.pdfthe vla is...
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What is the VLA?
The Very Large Array (VLA) is one of the world's premier astronomical radio observatories. The VLAconsists of 27 antennas arranged in a huge Y pattern up to 36km (22 miles) across -- roughly one and ahalf times the size of Washington, DC.
Each antenna is 25 meters (81 feet) in diameter; they are combined electronically to give the resolutionof 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 projectwas completed within the allotted budget.
Location:Plains of San Agustin, west of Socorro, New Mexico.
latitude = 34 04' 43.497" north❍
longitude = 107 37' 03.819" west❍
elevation = 2124 m❍
NRAO VLA Home Page: What is the VLA?
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Size:Each antenna:
25m in diameter, 230 tons.
The array:
There are four configurations: A array, with a maximum antenna separation of 36km; Barray -- 10km; C array -- 3.6km; and D array -- 1km. The telescopes are switched betweenthese 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 ourhighest frequency (43GHz) this gives a resolution of 0.04 arcseconds: sufficient to see a golf ballheld by a friend 150km (100 miles) away. Of course, very few golf balls contain high-power radiotransmitters...
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
P Band L Band CBand
XBand U Band K Band Q Band
Frequency(GHz) 0.30-0.34 1.34-1.73 4.5-5.0 8.0-8.8 14.4-15.4 22-24 40-50
Wavelength(cm) 90 20 6 3.6 2 1.3 0.7
Primarybeam
(arcmin)150 30 9 5.4 3 2 1
Highestresolution(arcsec)
6.0 1.4 0.4 0.24 0.14 0.08 0.05
SystemTemp 150-180.K 37-75.K 44.K 34.K 110.K 160-190.K 90-140.K
NRAO VLA Home Page: What is the VLA?
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How does it work?The VLA is an interferometer; this means that it operates by multiplying the data from each pair oftelescopes together to form interference patterns. The structure of those interference patterns, andhow they change with time as the earth rotates, reflect the structure of radio sources on the sky: wecan take these patterns and use a mathematical technique called the Fourier transform to makemaps.
Who uses it?The VLA is used primarily by astronomers from around the world. It's also occasionally used foratmospheric/weather studies, satellite tracking, and other miscellaneous science. If you would liketo 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 Astronomy Observatory (NRAO), which is a facilityof the National Science Foundation (NSF), operated under cooperative agreement by AssociatedUniversities, 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 VLAImages from the local website
Alan Bridle's beautiful jets
Recent resultsRecent press releases
Highlights of this month's VLA observations
VLA Home Page
Last modified 20 April 1999
NRAO VLA Home Page: What is the VLA?
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Some Aerial Views of the VLAClick on any image for a larger version. All photos are by Dave Finley, courtesy National RadioAstronomy 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.
Some Aerial Views of the VLA
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The North Arm of the VLA, looking South toward the center.
The center of the VLA, with the antennas in close configuration.
Some Aerial Views of the VLA
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A close-in look at the center of the VLA.
The VLA, with Tres Montosas in the background.
Some Aerial Views of the VLA
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Twilight on the VLA, looking Southwest.
The National Radio Astronomy Observatory is a facility of the National ScienceFoundation, operated under cooperative agreement by Associated Universities, Inc..
Some Aerial Views of the VLA
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Images from the Very Large Array
The Extra-galactic Radio Source Cygnus A ( 235k):●
The Supernova Remnant Cas A ( 369k): ●
NRAO Very Large Array Images
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The Arc at the Galactic Center ( 235k): ●
Last modified 28 November 1995
NRAO Very Large Array Images
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Images of Radio Galaxies and Quasars
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
Alan Bridle's Image Gallery
http://www.cv.nrao.edu/~abridle/images.htm [5/26/1999 1:26:05 PM]
National Radio AstronomyObservatory
Recent Press Releases
1999:Superfast Cosmic Jet "Hits the Wall"●
Astronomers Discover Rotating Disk Around Young, Massive Star●
"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 Milky Way●
Possible Analog for Early Solar System Disk Found●
Cosmic Flasher Reveals All●
Background Information: Magnetars, Soft Gamma-Ray Repeaters and the Most PowerfulMagnetic Fields in the Universe
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VLA Reveals Surprising Pair of Potential Planetary Systems●
VLA Observations Confirm Origin of Gamma Ray Bursts in Short-Lived Stars●
Background Information: Deciphering Gamma Ray Burst Physics With Radio Telescopes●
Strange, Bursting Star System Has Astronomers Scrambling●
VLA Shows "Boiling" in Atmosphere of Betelgeuse●
1997:Radio Observations Provide New Clues to Gamma Ray Fireball●
Astronomers Make First Images With Space Radio Telescope●
NRAO Recent Press Releases
http://www.aoc.nrao.edu/doc/pr/pr.html (1 of 3) [5/26/1999 1:26:20 PM]
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 Radio Telescope 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"
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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 CometHyakutake
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Research Teams Will Use Very Large Array To Study Close-Passing Comet●
Detecting Extrasolar Planets 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 Black Hole in Double-Star System Promises Exciting Yield of NewPhysics Data
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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
NRAO Recent Press Releases
http://www.aoc.nrao.edu/doc/pr/pr.html (2 of 3) [5/26/1999 1:26:20 PM]
NRAO Recent Press Releases
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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
NRAO Very Large Array Home Page
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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,pulsars)
●
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
NRAO Very Large Array Home Page
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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 quasar yetfound, at a distance of more than 12 billion light-years. They are studying radio emission that indicatesthe 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 beingformed. The existence of the heavy elements Carbon and Oxygen indicates, however, that some starsalready had lived through their life cycles even at that early age of the universe. A second team ofobservers 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 playin the formation of some types of galaxies.
Magnetic Fields on the Sun
Three teams of solar specialists will study the sun this month. Their observations will seek to learn aboutflaring loops on the sun and about the magnetic fields and heating in the sun's outer atmosphere, calledthe corona.
The Galactic Center
Two observing teams will study the center of our own Galaxy, the Milky Way. One will use a newsystem to observe the Galaxy's central region at low frequency (74 MHz) to seek to find new structuresnot 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 resultfrom the explosions that cause cosmic bursts of Gamma rays. In May 1997, the VLA made the first-everdetection of radio waves coming from a gamma-ray burster, and measured the emission from that object
VLA Current Observations
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for months afterward. As satellites with gamma-ray detectors continue to give rapid notice of thesebursts, the VLA, along with other ground-based observatories, will seek to detect the object atwavelengths longer than those of gamma rays. The VLA also detected radio emission from Gamma RayBursters that exploded on March 29, 1998. July 3, 1998, and January 23, 1999.
VLA Home Page
Last modified 30 April 1999
VLA Current Observations
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