View source for Very Large Array

{{Short description|Radio astronomy observatory located in New Mexico, united States}}
{{Cleanup bare URLs|date=August 2022}}
{{Infobox telescope
| map_caption = Location of the Very Large Array
}}
[[File:Plant ecologies on site.jpg|thumb|One of the 28 radio telescopes undergoing maintenance in "The Barn"<ref>{{cite web |url=https://public.nrao.edu/gallery/vla-antennas-and-the-barn/ |title=VLA Antennas and The Barn |access-date=19 May 2020}}</ref>]]
The '''Karl G. Jansky Very Large Array''' ('''VLA''') is a [[radio astronomy|centimeter-wavelength radio astronomy]] [[observatory]] located in central New Mexico on the [[Plains of San Agustin]], between the towns of [[Magdalena, New Mexico|Magdalena]] and [[Datil, New Mexico|Datil]], ~{{convert|50|mi}} west of [[Socorro, New Mexico|Socorro]]. The VLA comprises twenty-eight 25-meter radio telescopes (twenty-seven of which are operational while one is always rotating through maintenance) deployed in a Y-shaped array and all the equipment, instrumentation, and computing power to function as an [[astronomical interferometer|interferometer]]. Each of the massive telescopes is mounted on double parallel railroad tracks, so the radius and density of the array can be transformed to adjust the balance between its angular resolution and its surface brightness sensitivity.<ref>http://www.vla.nrao.edu</ref> Astronomers using the VLA have made key observations of [[black hole]]s and [[protoplanetary disk]]s around [[Stellar age estimation|young stars]], discovered magnetic filaments and traced complex gas motions at the [[Milky Way]]'s center, probed the Universe's cosmological parameters, and provided new knowledge about the physical mechanisms that produce [[Radio wave|radio emission]].

The VLA stands at an elevation of {{convert|6970|ft}} above sea level. It is a component of the [[National Radio Astronomy Observatory]] (NRAO).<ref name="visit">{{cite web |url=https://public.nrao.edu/tours/visitvla |title=Visit the VLA |work=public.nrao.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref> The NRAO is a facility of the [[National Science Foundation ]] operated under cooperative agreement by [[Associated Universities, Inc.|Associated Universities, Inc]].

== Characteristics ==
The [[radio telescope]] comprises 27 independent antennas in use at a given time plus one spare, each of which has a dish diameter of 25&nbsp;meters (82&nbsp;feet) and weighs {{convert|209|MT|ST|lk=on}}.<ref>{{cite web |url=http://www.vla.nrao.edu/ |title=Welcome to the Very Large Array! |work=vla.nrao.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref> The antennas are distributed along the three arms of a track, shaped in a wye (or Y) -configuration, (each of which measures {{convert|21|km}} long). Using the rail tracks that follow each of these arms—and that, at one point, intersect with [[U.S. Route 60 in New Mexico|U.S. Route 60]] at a level crossing—and a specially designed lifting locomotive ("Hein's Trein"),<ref>{{cite news |first=Joe |last=Holley |url=https://www.washingtonpost.com/wp-dyn/content/article/2008/05/28/AR2008052803211.html |title=Hein Hvatum, 85; Engineered Telescope to the Heavens |newspaper=[[The Washington Post]] |date=May 29, 2008 |access-date=2015-03-24}}</ref> the antennas can be physically relocated to a number of prepared positions, allowing [[aperture synthesis]] [[interferometry]] with up to 351 independent baselines: in essence, the array acts as a single antenna with a variable diameter. The [[angular resolution]] that can be reached is between 0.2 and 0.04 [[arcseconds]].<ref name="specs">{{Cite web|url=https://public.nrao.edu/telescopes/vla/vla-basics|title = Very Large Array}}</ref>

There are four commonly used configurations, designated A (the largest) through D (the tightest, when all the dishes are within {{convert|600|m}} of the center point). The observatory normally cycles through all the various possible configurations (including several hybrids) every 16 months; the antennas are moved every three to four months.  Moves to smaller configurations are done in two stages, first shortening the east and west arms and later shortening the north arm.  This allows for a short period of improved imaging of extremely northerly or southerly sources.{{citation needed|date=March 2015}}

The frequency coverage is {{frequency|74|MHz}} to {{frequency|50|GHz}} (400&nbsp;cm to 0.7&nbsp;cm).<ref name="overview">{{cite web |url=http://www.vla.nrao.edu/genpub/overview/ |title=An Overview of the Very Large Array |work=vla.nrao.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref>

The Pete V. Domenici Science [[Array Operations Center|Operations Center]] (DSOC) for the VLA is located on the campus of the [[New Mexico Institute of Mining and Technology]] in [[Socorro, New Mexico]]. The DSOC also serves as the control center for the [[Very Long Baseline Array]] (VLBA), a [[Very Long Baseline Interferometry|VLBI]] array of ten 25-meter dishes located from [[Hawaii]] in the west to the [[U.S. Virgin Islands]] in the east that constitutes the world's largest dedicated, full-time astronomical instrument.<ref>{{cite web |url=https://science.nrao.edu/facilities/vlba |title=Very Long Baseline Array |work=science.nrao.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref>

==Upgrade and renaming==
In 2011, a decade-long upgrade project resulted in the VLA expanding its technical capacities by factors of up to 8,000. The 1970s-era electronics were replaced with state-of-the-art equipment. To reflect this increased capacity, VLA officials asked for input from both the scientific community and the public in coming up with a new name for the array, and in January 2012 it was announced that the array would be renamed the "[[Karl Guthe Jansky|Karl G. Jansky]] Very Large Array".<ref>{{cite news |agency=Associated Press |url=https://abcnews.go.com/Technology/wireStory/mexico-radio-telescope-seeking-14740459 |title=New Mexico Radio Telescope Seeking New Name |work=ABC News |date=October 14, 2011 |archive-url=https://web.archive.org/web/20111016030735/https://abcnews.go.com/Technology/wireStory/mexico-radio-telescope-seeking-14740459 |archive-date=2011-10-16}}</ref><ref>{{cite news |first=Jason |last=Palmer |url=https://www.bbc.co.uk/news/science-environment-15307169 |title=Very Large Array telescope in public call for new name |work=BBC News |date=October 15, 2011 |access-date=2015-03-24}}</ref><ref>{{cite web |first=Dave |last=Finley |url=http://www.nrao.edu/pr/2012/jansky/ |title=Iconic Telescope Renamed to Honor Founder of Radio Astronomy |work=NRAO.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref> On March 31, 2012, the VLA was officially renamed in a ceremony inside the Antenna Assembly Building.<ref>{{cite web |first=Dave |last=Finley |url=http://www.nrao.edu/pr/2012/rededicate/ |title=Famous Radio Telescope Officially Gets New Name |work=NRAO.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref>

==Key science==
The VLA is a multi-purpose instrument designed to allow investigations of many astronomical objects, including [[Radio galaxy|radio galaxies]], [[quasar]]s, [[pulsar]]s, [[supernova]] remnants, [[gamma-ray burst]]s, radio-emitting [[star]]s, the [[sun]] and [[planet]]s, [[astrophysical maser]]s, [[black hole]]s, and the [[hydrogen]] gas that constitutes a large portion of the [[Milky Way]] galaxy as well as external galaxies.  In 1989 the VLA was used to receive [[radio]] communications from the [[Voyager 2]] spacecraft as it flew by [[Neptune]].<ref name="Taylor">{{cite book|editor-last=Taylor|editor-first=Jim|title=Deep Space Communications|date=2016|publisher=John Wiley & Sons | isbn=978-1-119-16902-4 | page=67|url=https://books.google.com/books?id=ucjeDAAAQBAJ&pg=PA67}}</ref> A search of the galaxies M31 and M32 was conducted in December 2014 through January 2015 with the intent of quickly searching trillions of systems for extremely powerful signals from advanced civilizations.<ref>{{cite journal|last1=Gray|first1=Robert H.|last2=Mooley|first2=Kunal|title=A VLA Search for Radio Signals from M31 and M33|journal=The Astronomical Journal|date=14 February 2017|volume=153|issue=3|pages=110|doi=10.3847/1538-3881/153/3/110|arxiv = 1702.03301 |bibcode = 2017AJ....153..110G |s2cid=119376407}}</ref>

It has been used to carry out several large surveys of radio sources, including the [[NRAO VLA Sky Survey]] and [[Faint Images of the Radio Sky at Twenty-Centimeters]].

In September 2017 the [[VLA Sky Survey]] (VLASS) began.<ref name="Murphy">{{cite web|last1=Murphy|first1=Davis|title=VLA Sky Survey|url=https://science.nrao.edu/science/surveys/vlass|website=National Radio Astronomy Observatory|access-date=30 September 2017}}</ref> This survey will cover the entire sky visible to the VLA (80% of the Earth's sky) in three full scans.<ref name="Barbuzano">{{cite web|last1=Barbuzano|first1=Javier|title=Iconic Radio Telescope Begins 7-year Search for New Objects|url=http://www.skyandtelescope.com/astronomy-news/iconic-radio-telescope-begins-search/|website=Sky & Telescope|date=26 September 2017|access-date=30 September 2017}}</ref> Astronomers expect to find about 10 million new objects with the survey&nbsp;— four times more than what is presently known.<ref name="Barbuzano" />

==History==
The driving force for the development of the VLA was [[List of members of the National Academy of Sciences (Astronomy)|David S. Heeschen]]. He is noted as having "sustained and guided the development of the best radio astronomy observatory in the world for sixteen years."<ref>{{cite book |first1=Wallace |last1=Tucker |first2=Karen |last2=Tucker |title=The Cosmic Inquirers: Modern Telescopes and Their Makers |publisher=Harvard University Press |year=1986 |isbn=0674174356}}</ref> [[United States Congress|Congressional]] approval for the VLA project was given in August 1972, and construction began some six months later. The first antenna was put into place in September 1975 and the complex was formally inaugurated in 1980, after a total investment of {{US$|78500000|1980}}.<ref name="overview"/> It was the largest configuration of radio telescopes in the world.

During construction in 1975, workers laying the tracks for the northern arm of the array discovered a human skeleton north of [[US-60]]. A year later, the remains were identified as belonging to a male airline passenger who was ejected from [[National Airlines Flight 27]] at {{convert|39,000|ft|m}} two years earlier, after the [[McDonnell Douglas DC-10|DC-10-10]] servicing the flight (N60NA) experienced an [[Turbine engine failure|uncontained engine failure]], causing [[Cabin pressure#Loss of pressurization|cabin decompression]].<ref name=Mondout>{{cite web |last=Mondout |first=Patrick |title=Curious Crew Nearly Crashes DC-10 |url=http://www.super70s.com/Super70s/Tech/Aviation/Disasters/73-11-03%28National%29.asp |accessdate=2010-11-21 |url-status=dead |archiveurl=https://web.archive.org/web/20110408023924/http://www.super70s.com/super70s/tech/aviation/disasters/73-11-03(National).asp |archivedate=2011-04-08 }}</ref><ref>{{cite news|last=Harden |first=Paul |title=Aircraft Down |url=https://dchieftain.com/news/aircraft-down/article_23a78c5b-7d34-5684-89ee-0f0a5de0c513.html |accessdate=2018-10-24 |newspaper=El Defensor Chieftain |date=2010-06-05 |archive-url=https://web.archive.org/web/20200815002131/https://dchieftain.com/news/aircraft-down/article_23a78c5b-7d34-5684-89ee-0f0a5de0c513.html |archive-date=2020-08-15 }}</ref>

With a view to upgrading the venerable 1970s technology with which the VLA was built, the VLA has evolved into the Expanded Very Large Array (EVLA). The upgrade has enhanced the instrument's sensitivity, [[frequency]] range, and resolution with the installation of new hardware at the San Agustin site. A second phase of this upgrade may add up to eight additional dishes in other parts of the state of [[New Mexico]], up to {{convert|300|km|order=flip}} away, if funded.<ref>{{cite web |url=http://www.aoc.nrao.edu/evla/ |title=The Expanded Very Large Array Project: A Radio Telescope to Resolve Cosmic Evolution |work=aoc.nrao.edu |publisher=National Radio Astronomy Observatory |access-date=2015-03-24}}</ref>

[[Magdalena Ridge Observatory]] is a new observatory a few miles south of the VLA,and is run by VLA collaborator [[New Mexico Tech]]. Under construction at this site is a ten-element optical [[interferometer]].

== Tourism ==
[[File:Bracewell Sundial.jpg|thumb|The Bracewell Radio Sundial on the VLA walking tour, seen from the south. Named for [[Ronald N. Bracewell]], this sundial marks on the ground positions of the shadow of the central sphere (the [[gnomon]]) at different times of day and times of year. The shadow on Dec 22, 2017 falls very near the [[winter solstice]] line and the 1:00 PM (solar time) mark.  The other two lines of markers north of the gnomon are for the [[equinox]]es and the [[summer solstice]].  Additional lines of markers south of the gnomon mark positions of "shadows" of the radio sources [[Cygnus A]] and [[Cassiopeia A]]. The posts at the back of the sundial were recovered from Bracewell's radio telescope array at [[Stanford University]], abandoned in 1980, where they had been signed by visitors with chisels at his invitation.]]

The VLA is located between the towns of [[Magdalena, New Mexico|Magdalena]] and [[Datil, New Mexico|Datil]], about {{convert|50|mi}} west of [[Socorro, New Mexico]]. [[U.S. Route 60 in New Mexico|U.S. Route 60]] passes east–west through the complex.{{citation needed|date=July 2017}}

The VLA site is open to visitors with paid admission.<ref>{{cite web
|url=https://public.nrao.edu/visit/very-large-array/#hours
|title=Visit the Very Large Array – National Radio Astronomy Observatory
|access-date=2022-10-08}}</ref> A visitor center houses a small museum, theater, and a gift shop.  A self-guided walking tour is available, as the visitor center is not staffed continuously.  Visitors unfamiliar with the area are warned that there is little food on site, or in the sparsely populated surroundings; those unfamiliar with the high desert are warned that the weather is quite variable, and can remain cold into April.<ref name="visit"/> For those who cannot travel to the site, the NRAO created a virtual tour of the VLA called the ''VLA Explorer''.<ref>{{cite web|title=The VLA Explorer|url=https://public.nrao.edu/special-features/vla-explorer/|website=National Radio Astronomy Observatory|access-date=30 September 2017}}</ref>

The VLA site was previously closed to visitors from March 2020 through October 2022.<ref>{{cite web
|url=https://web.archive.org/web/20201003233549/https://public.nrao.edu/news/covid19/
|title=Latest Updates on COVID-19 Measures from NRAO, ALMA, GBO - National Radio Astronomy Observatory
|date=2020-03-13
|access-date=2020-10-03
|quote=All our facilities are CLOSED to the public!}}</ref> <ref>{{cite web
|url=https://web.archive.org/web/20221008174018/https://public.nrao.edu/news/covid19/
|title=Latest Updates on COVID-19 Measures from NRAO, ALMA, GBO - National Radio Astronomy Observatory
|date=2022-09-28
|access-date=2022-10-03}}</ref>

{{Panorama
|image   = File:VLA pano.jpg
|height  = 200
|caption = The cross rail track structure of the VLA, including an empty antenna mount station on the right (the three concrete piers that the antenna's triangular base mounts to)
}}

==In popular culture==
The VLA has appeared repeatedly in popular culture since its construction.

* The VLA is present in the 1984 movie ''[[2010 (film)|2010: The Year We Make Contact]]'', as the location where Dr. Floyd and Dimitri Moiseyevich discuss the upcoming missions to Jupiter.<ref name="Hughes2014">{{cite book|author=Howard Hughes|title=Outer Limits: The Filmgoers' Guide to the Great Science-fiction Films|url=https://archive.org/details/outerlimitsfilmg0000hugh|url-access=registration|date=30 May 2014|publisher=I.B.Tauris|isbn=978-1-78076-166-4|pages=[https://archive.org/details/outerlimitsfilmg0000hugh/page/91 91]–}}</ref>
* The VLA is present in the 1997 movie ''[[Contact (1997 American film)|Contact]]'', as the location where the alien signal is first detected.<ref name="Hughes2014"/><ref>{{cite book|title=Guidebook for the Scientific Traveler|year = 2010|url=https://books.google.com/books?id=2nDPxIRqakcC&pg=PA86|publisher=Rutgers University Press|isbn=978-0-8135-4918-7|pages=86–}}</ref>
* British artist Keith Tyson created a 300 piece sculpture called ''[[Keith Tyson#Large Field Array|Large Field Array]]'' (2006–2007) named after the VLA.<ref>{{cite web |url=http://www.artnet.com/magazineus/reviews/robinson/robinson9-11-07.asp |first=Walter |last=Robinson |title=Weekend Update |work=Artnet.com |date=November 11, 2007 |publisher=Artnet Worldwide Corporation |access-date=2015-03-24}}</ref>
* In the 2009 science-fiction film ''[[Terminator Salvation]]'', the VLA is the location of a [[Skynet (Terminator)|Skynet]] facility. At the beginning of the film the site is attacked by Resistance forces.<ref name="Hughes2014"/><ref name="II2013">{{cite book|author=Joseph T. Page II|title=New Mexico Space Trail|url=https://books.google.com/books?id=pgs7BAAAQBAJ&pg=PA59|date=6 May 2013|publisher=Arcadia Publishing|isbn=978-1-4396-4328-0|pages=59–}}</ref>
*A parody of the VLA, known as ''The Big Ear'', appears in the 2004 action-adventure video game ''[[Grand Theft Auto: San Andreas]]'', sharing its name with a SETI project from [[Ohio State University]]. A single huge dish forms ''The Big Ear'' in-game.<ref>{{cite web|url=https://www.grandtheftwiki.com/The_Big_Ear|title=The Big Ear: Grand Theft Wiki, The GTA Wiki|access-date=19 May 2022}}</ref>
* In Season 2, Episode 1 of the BBC series "Luther", which first aired 29 sep 2011, the character Alice Morgan (played by [[Ruth Wilson]]) tells Luther that "I've always wanted to go and see the Very Large Array in New Mexico. It's not the biggest in the world, of course, or the most iconic, but I grew up wanting to see it. It's quite spectacular, out there in the desert."

== Trivia ==
* An image of the Very Large Array appeared on the cover of [[Bon Jovi]]'s 2002 studio album, ''[[Bounce (Bon Jovi album)|Bounce]]''.

== See also ==
* [[Allen Telescope Array]] (ATA)
* [[Atacama Large Millimeter Array]] (ALMA)
* [[Green Bank Telescope]] (GBT)
* [[Lake San Agustín]], which once stood where the VLA is now
* [[List of radio telescopes]]
* [[Square Kilometre Array]] (SKA)
* [[Very-long-baseline interferometry]] (VLBI)
* [[Very Small Array]] (VSA)

== References ==
{{Reflist|30em}}

== External links ==
{{Commons category}}
* {{Official website|http://www.vla.nrao.edu/}}
* [http://www.nrao.edu/explorer/vla/ VLA Explorer]
* [https://science.nrao.edu/facilities/vla The Karl G. Jansky Very Large Array] page at [[NRAO]]
* {{APOD |date=14 May 2006 |title=The Very Large Array of Radio Telescopes}}
* [https://public.nrao.edu/ngvla/ The Next Generation Very Large Array] (ngVLA)

{{Radio-astronomy|state=uncollapsed}}
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[[Category:Astronomical observatories in New Mexico]]
[[Category:Buildings and structures in Socorro County, New Mexico]]
[[Category:Interferometric telescopes]]
[[Category:Museums in Socorro County, New Mexico]]
[[Category:Radio telescopes]]
[[Category:Science museums in New Mexico]]
[[Category:1980 establishments in New Mexico]]