Atacama Large Millimeter Array
Encyclopedia
The Atacama Large Millimeter/sub-millimeter Array (ALMA) is an array
of radio telescopes in the Atacama desert of northern Chile. Since a high and dry site is crucial to millimeter wavelength operations, the array is being constructed on the Chajnantor plateau
at 5000 metres altitude
. Consisting of 66 12-meter and 7-meter diameter radio telescope
s observing at millimeter and sub-millimeter wavelength
s, ALMA is expected to provide insight on star birth during the early universe and detailed imaging of local star and planet formation.
ALMA is an international partnership between Europe, North America, East Asia and the Republic of Chile
. Costing more than a billion
US dollars, it is the most expensive ground-based telescope currently under construction. ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011. The project is scheduled to be fully operational by the end of 2012.
s of 0.3 to 9.6 mm. The array will have much higher sensitivity and higher resolution than existing sub-millimeter telescopes such as the single-dish James Clerk Maxwell Telescope
or existing interferometer networks such as the Submillimeter Array
or the Institut de Radio Astronomie Millimétrique (IRAM) Plateau de Bure
facility.
The antennas can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable "zoom", similar in its concept to that employed at the Very Large Array
(VLA) site in New Mexico, US.
The high sensitivity is mainly achieved through the large numbers of telescopes that will make up the array.
The telescopes are provided by the European, North American and East Asian partners of ALMA. The American and European partners have each placed orders for twenty-five 12-metre diameter antennas, that will compose the main array. East Asia is contributing 16 antennas (four 12-metre diameter and twelve 7-metre diameter antennas) in the form of the Atacama Compact Array (ACA) which is also part of the enhanced ALMA.
By using smaller antennas than ALMA, larger fields of view can be imaged at a given frequency using ACA. Moving the antennas closer together will enable the imaging of sources of larger angular extent. The ACA will work together with the main array in order to enhance the latter's wide-field imaging capability.
The first step toward the creation of what would become ALMA came in 1997, when the NRAO
(National Radio Astronomy Observatory) and the ESO
(European Southern Observatory) agreed to pursue a common project that merged the MMA and LSA. The merged array combined the sensitivity of the LSA with the frequency coverage and superior site of the MMA. ESO and NRAO worked together in technical, science, and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain (the latter became a member of ESO later).
A series of resolutions and agreements led to the choice of "Atacama Large Millimeter Array", or ALMA, as the name of the new array in March 1999 and the signing of the ALMA Agreement on February 25, 2003, between the North American and European parties. Following mutual discussions over several years, the ALMA Project received a proposal from the NAOJ
(National Astronomical Observatory of Japan) whereby Japan would provide the ACA (Atacama Compact Array) and three additional receiver bands for the large array, to form Enhanced ALMA. Further discussions between ALMA and NAOJ led to the signing of a high-level agreement on September 14, 2004, that makes Japan an official participant in Enhanced ALMA, to be known as the Atacama Large Millimeter/sub-millimeter Array.
During an early stage of the planning of ALMA, it was decided to employ ALMA antennas designed and constructed by known companies in North America, Europe and Japan rather than using one single design. This was mainly for political reasons. Although very different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMA's stringent requirements.
and European Southern Observatory (ESO
). The array has been extended with the help of the new Japanese, Taiwanese, and Chilean partners. ALMA is the largest and most expensive ground-based astronomical project currently under construction (current cost estimate is US$1.3 billion).
Partners
General Dynamics
C4 Systems has been contracted by Associated Universities, Inc. to provide twenty-five of the 12m antennae, and European manufacturer Thales Alenia Space
has been signed up to provide the other twenty-five principle antennae (in the largest-ever European industrial contract). The first antenna was delivered in 2008, and the rest will be delivered at about one per month, finishing in 2011.
antennas from the Operations Support Facility at 2900 m altitude to the site at 5000 m presents enormous problems. The solution chosen is to use two custom 28-wheel self-loading heavy hauler
s. The vehicles are made by Scheuerle Fahrzeugfabrik in Germany and each is 10 m wide, 20 m long and 6 m high, weighing 130 tonnes. They are powered by twin 500 kW diesel engine
s.
The transporters, which feature a driver's seat designed to accommodate an oxygen
tank to aid breathing the thin high-altitude air, can pick up the antennas and place them precisely at the site. The first vehicle was completed and tested in July 2007. Both transporters were delivered to the ALMA Operations Support Facility (OSF) in Chile on February 15, 2008.
On July 7, 2008 an ALMA transporter for the first time moved an antenna, moving it from inside the antenna assembly building (Site Erection Facility) to a pad outside the building for testing (holographic surface measurements). The antenna was of the North American VertexRSI design.
During Fall, 2009 the first three antennas were transported one by one to the Array Operations Site. At the end of 2009, a team of ALMA astronomers and engineers successfully linked three of the observatory's advanced antennas at the 16500 feet (5,029.2 m)-elevation observing site thus finishing the first stage of assembly and integration of the fledgling array. Linking three antennas to work in unison for the first time allowed the ALMA team to correct errors that can arise when only two antennas are used, thus paving the way for precise, high-resolution imaging. With this key step, commissioning of the instrument began January 22, 2010.
On July 28, 2011, the first European antenna for ALMA arrived at the Chajnantor plateau, 5000 meters above sea level, to join antennas already in place from the other international partners, bringing the total number to 16. It is the number of antennas specified for ALMA to begin its first science observations, and is therefore an important milestone for the project.
The target of the observation was a pair of colliding galaxies with dramatically distorted shapes, known as the Antennae Galaxies. Although LMA did not observe the entire galaxy merger, the result is the best submillimeter-wavelength image ever made of the Antennae Galaxies, showing the clouds of dense cold gas from which new stars form, which cannot be seen using visible light.
(ESO), in North America by the U.S. National Science Foundation
(NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council
of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences
of Japan (NINS) in cooperation with the Academia Sinica
(AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory
(NRAO), which is managed by Associated Universities, Inc
(AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan
(NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
) has been further subdivided into ARC-nodes located across Europe in Bonn-Bochum-Cologne, Bologna, Ondřejov, Onsala
, IRAM (Grenoble), Leiden and JBCA
(Manchester).
The core purpose of the ARC is to: assist the user community with the preparation of observing proposals, ensure observing programs meet their scientific goals efficiently, run a help-desk for submitting proposals and observing programs, delivering the data to principal investigators, maintenance of the ALMA data archive, assistance with the calibration of data and providing user feedback.
Astronomical interferometer
An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry....
of radio telescopes in the Atacama desert of northern Chile. Since a high and dry site is crucial to millimeter wavelength operations, the array is being constructed on the Chajnantor plateau
Llano de Chajnantor Observatory
Llano de Chajnantor Observatory is an astronomical observatory located at an altitude of 5,104 m in the Chilean Atacama desert, 50 kilometers to the east of San Pedro de Atacama. It is a very dry site - inhospitable to humans - but an excellent site for submillimetre astronomy...
at 5000 metres altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
. Consisting of 66 12-meter and 7-meter diameter radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
s observing at millimeter and sub-millimeter wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s, ALMA is expected to provide insight on star birth during the early universe and detailed imaging of local star and planet formation.
ALMA is an international partnership between Europe, North America, East Asia and the Republic of Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
. Costing more than a billion
1000000000 (number)
1,000,000,000 is the natural number following 999,999,999 and preceding 1,000,000,001.In scientific notation, it is written as 109....
US dollars, it is the most expensive ground-based telescope currently under construction. ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011. The project is scheduled to be fully operational by the end of 2012.
Overview
The initial ALMA array will be composed of 66 high-precision antennas, and operate at wavelengthWavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s of 0.3 to 9.6 mm. The array will have much higher sensitivity and higher resolution than existing sub-millimeter telescopes such as the single-dish James Clerk Maxwell Telescope
James Clerk Maxwell Telescope
The James Clerk Maxwell Telescope is a submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. Its primary mirror is 15 metres across: it is the largest astronomical telescope that operates in submillimetre wavelengths of the electromagnetic spectrum...
or existing interferometer networks such as the Submillimeter Array
Submillimeter Array
The Submillimeter Array consists of eight diameter radio telescopes arranged as an interferometer for submillimeter wavelength observations. It is the first purpose-built submillimeter interferometer, constructed after successful interferometry experiments using the pre-existing James Clerk...
or the Institut de Radio Astronomie Millimétrique (IRAM) Plateau de Bure
Plateau de Bure Interferometer
The Plateau de Bure Interferometer is a six-antenna interferometer on the Plateau de Bure in the French Alps, operated by the Institut de radioastronomie millimétrique....
facility.
The antennas can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable "zoom", similar in its concept to that employed at the Very Large Array
Very Large Array
The Very Large Array is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some fifty miles west of Socorro, New Mexico, USA...
(VLA) site in New Mexico, US.
The high sensitivity is mainly achieved through the large numbers of telescopes that will make up the array.
The telescopes are provided by the European, North American and East Asian partners of ALMA. The American and European partners have each placed orders for twenty-five 12-metre diameter antennas, that will compose the main array. East Asia is contributing 16 antennas (four 12-metre diameter and twelve 7-metre diameter antennas) in the form of the Atacama Compact Array (ACA) which is also part of the enhanced ALMA.
By using smaller antennas than ALMA, larger fields of view can be imaged at a given frequency using ACA. Moving the antennas closer together will enable the imaging of sources of larger angular extent. The ACA will work together with the main array in order to enhance the latter's wide-field imaging capability.
History
ALMA has its conceptual roots in three astronomical projects: the Millimetre Array (MMA) of the United States, the Large Southern Array (LSA) of Europe, and the Large Millimetre Array (LMA) of Japan.The first step toward the creation of what would become ALMA came in 1997, when the NRAO
National Radio Astronomy Observatory
The National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy...
(National Radio Astronomy Observatory) and the ESO
European Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
(European Southern Observatory) agreed to pursue a common project that merged the MMA and LSA. The merged array combined the sensitivity of the LSA with the frequency coverage and superior site of the MMA. ESO and NRAO worked together in technical, science, and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain (the latter became a member of ESO later).
A series of resolutions and agreements led to the choice of "Atacama Large Millimeter Array", or ALMA, as the name of the new array in March 1999 and the signing of the ALMA Agreement on February 25, 2003, between the North American and European parties. Following mutual discussions over several years, the ALMA Project received a proposal from the NAOJ
National Astronomical Observatory of Japan
The is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
(National Astronomical Observatory of Japan) whereby Japan would provide the ACA (Atacama Compact Array) and three additional receiver bands for the large array, to form Enhanced ALMA. Further discussions between ALMA and NAOJ led to the signing of a high-level agreement on September 14, 2004, that makes Japan an official participant in Enhanced ALMA, to be known as the Atacama Large Millimeter/sub-millimeter Array.
During an early stage of the planning of ALMA, it was decided to employ ALMA antennas designed and constructed by known companies in North America, Europe and Japan rather than using one single design. This was mainly for political reasons. Although very different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMA's stringent requirements.
Funding
ALMA was initially a 50-50 collaboration between the US National Radio Astronomy ObservatoryNational Radio Astronomy Observatory
The National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy...
and European Southern Observatory (ESO
ESO
ESO, as a three-letter abbreviation, may stand for:* European Southern Observatory* Ensemble Studios Online* English Symphony Orchestra* Edmonton Symphony Orchestra* Executive Stock Options...
). The array has been extended with the help of the new Japanese, Taiwanese, and Chilean partners. ALMA is the largest and most expensive ground-based astronomical project currently under construction (current cost estimate is US$1.3 billion).
Partners
- European Southern ObservatoryEuropean Southern ObservatoryThe European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
and the European Regional Support Centre - National Science FoundationNational Science FoundationThe National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
via the National Radio Astronomy ObservatoryNational Radio Astronomy ObservatoryThe National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy...
and the North American ALMA Science Center - National Research Council of CanadaNational Research Council of CanadaThe National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
- National Astronomical Observatory of JapanNational Astronomical Observatory of JapanThe is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
(NAOJ) under the National Institutes of Natural Sciences (NINS) - ALMA-TaiwanTaiwanTaiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
at the Academia SinicaAcademia SinicaThe Academia Sinica , headquartered in the Nangang District of Taipei, is the national academy of Taiwan. It supports research activities in a wide variety of disciplines, ranging from mathematical and physical sciences, to life sciences, and to humanities and social sciences.Academia Sinica has...
Institute of Astronomy & Astrophysics (ASIAA) - Republic of Chile
Assembly
The complex will be built primarily by European, U.S., Japanese and Canadian companies and universities. Three prototype antennae have undergone evaluation at the Very Large Array site in New Mexico since 2002.General Dynamics
General Dynamics
General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...
C4 Systems has been contracted by Associated Universities, Inc. to provide twenty-five of the 12m antennae, and European manufacturer Thales Alenia Space
Thales Alenia Space
Thales Alenia Space is an aerospace company born after the Thales Group bought the participation of Alcatel in the two joint-ventures between Alcatel and Finmeccanica, Alcatel Alenia Space and Telespazio.-History:...
has been signed up to provide the other twenty-five principle antennae (in the largest-ever European industrial contract). The first antenna was delivered in 2008, and the rest will be delivered at about one per month, finishing in 2011.
Transporting antennas to the site
Transporting the 115 tonneTonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
antennas from the Operations Support Facility at 2900 m altitude to the site at 5000 m presents enormous problems. The solution chosen is to use two custom 28-wheel self-loading heavy hauler
Heavy hauler
A heavy hauler is a very large transporter for moving oversize loads which are toolarge to go on a highway without an escort and special permit.-Types of vehicles:...
s. The vehicles are made by Scheuerle Fahrzeugfabrik in Germany and each is 10 m wide, 20 m long and 6 m high, weighing 130 tonnes. They are powered by twin 500 kW diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s.
The transporters, which feature a driver's seat designed to accommodate an oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
tank to aid breathing the thin high-altitude air, can pick up the antennas and place them precisely at the site. The first vehicle was completed and tested in July 2007. Both transporters were delivered to the ALMA Operations Support Facility (OSF) in Chile on February 15, 2008.
On July 7, 2008 an ALMA transporter for the first time moved an antenna, moving it from inside the antenna assembly building (Site Erection Facility) to a pad outside the building for testing (holographic surface measurements). The antenna was of the North American VertexRSI design.
During Fall, 2009 the first three antennas were transported one by one to the Array Operations Site. At the end of 2009, a team of ALMA astronomers and engineers successfully linked three of the observatory's advanced antennas at the 16500 feet (5,029.2 m)-elevation observing site thus finishing the first stage of assembly and integration of the fledgling array. Linking three antennas to work in unison for the first time allowed the ALMA team to correct errors that can arise when only two antennas are used, thus paving the way for precise, high-resolution imaging. With this key step, commissioning of the instrument began January 22, 2010.
On July 28, 2011, the first European antenna for ALMA arrived at the Chajnantor plateau, 5000 meters above sea level, to join antennas already in place from the other international partners, bringing the total number to 16. It is the number of antennas specified for ALMA to begin its first science observations, and is therefore an important milestone for the project.
Images from Initial Testing
By the summer of 2011 sufficient telescopes were operational during the extensive program of testing prior to the Early Science phase for the first images to be captured. These early images give a first glimpse of the potential of the new array that will produce much better quality images in the future as the scale of the array continues to increase.The target of the observation was a pair of colliding galaxies with dramatically distorted shapes, known as the Antennae Galaxies. Although LMA did not observe the entire galaxy merger, the result is the best submillimeter-wavelength image ever made of the Antennae Galaxies, showing the clouds of dense cold gas from which new stars form, which cannot be seen using visible light.
Global collaboration
The Atacama Large Millimetre/sub-millimetre Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern ObservatoryEuropean Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
(ESO), in North America by the U.S. National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
(NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council
National Science Council
The National Science Council is the main governmental promotion and funding body for science research in Taiwan, Republic of China. It is a governmental body under the Executive Yuan.-External links:* *...
of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences
National Institutes of Natural Sciences, Japan
The is an inter-university research institute corporation consisting of five member institutes: the National Astronomical Observatory , the National Institute for fusion Science , the National Institute for Basic Biology , the National Institute for Physiological Sciences , and the Institutes for...
of Japan (NINS) in cooperation with the Academia Sinica
Academia Sinica
The Academia Sinica , headquartered in the Nangang District of Taipei, is the national academy of Taiwan. It supports research activities in a wide variety of disciplines, ranging from mathematical and physical sciences, to life sciences, and to humanities and social sciences.Academia Sinica has...
(AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory
National Radio Astronomy Observatory
The National Radio Astronomy Observatory is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy...
(NRAO), which is managed by Associated Universities, Inc
Associated Universities, Inc
Associated Universities, Inc. is a research management corporation that builds and operates facilities for the research community. AUI is a not-for-profit 501 corporation, headquartered in Washington, DC. The President and Chief Executive Officer is Ethan J. Schreier...
(AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan
National Astronomical Observatory of Japan
The is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
(NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
ALMA regional centre (ARC)
The ALMA regional centre (ARC) has been designed as an interface between user communities of the major contributors of the ALMA project and the JAO. Activates for operating the ARC have also divided into the three main regions involved (Europe, North America and East Asia). The European ARC (led by ESOEuropean Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
) has been further subdivided into ARC-nodes located across Europe in Bonn-Bochum-Cologne, Bologna, Ondřejov, Onsala
Onsala Space Observatory
Onsala Space Observatory , the Swedish National Facility for Radio Astronomy, provides scientists with equipment to study the Earth and the rest of the Universe. The observatory operates two radio telescopes in Onsala, 45 km south of Göteborg, and takes part in several international projects...
, IRAM (Grenoble), Leiden and JBCA
Jodrell Bank Centre for Astrophysics
The Jodrell Bank Centre for Astrophysics at the University of Manchester, is among the largest astrophysics groups in the UK. It includes the world leading facilities of the Jodrell Bank Observatory, the MERLIN/VLBI National Facility, the Development Office of the Square Kilometre Array, and the...
(Manchester).
The core purpose of the ARC is to: assist the user community with the preparation of observing proposals, ensure observing programs meet their scientific goals efficiently, run a help-desk for submitting proposals and observing programs, delivering the data to principal investigators, maintenance of the ALMA data archive, assistance with the calibration of data and providing user feedback.
Project detail
- At least 50 antennas of 12 m diameter located at an elevation of 5,000 m at Llano de Chajnantor ObservatoryLlano de Chajnantor ObservatoryLlano de Chajnantor Observatory is an astronomical observatory located at an altitude of 5,104 m in the Chilean Atacama desert, 50 kilometers to the east of San Pedro de Atacama. It is a very dry site - inhospitable to humans - but an excellent site for submillimetre astronomy...
, enhanced by a compact array of 4 x 12 m and 12 x 7 m antennas (consortium currently considering to build 50 or 64 http://www.sciencemag.org/cgi/content/full/312/5776/990http://www.nature.com/nature/journal/v439/n7076/full/439526a.html) - ImagingDigital imagingDigital imaging or digital image acquisition is the creation of digital images, typically from a physical scene. The term is often assumed to imply or include the processing, compression, storage, printing, and display of such images...
instrument in all atmospheric windowsRadio windowThe radio window is the range of frequencies of electromagnetic radiation that the earth's atmosphere lets through. The wavelengths in the radio window run from about one centimetre to about eleven-metre waves.-See also:*Astronomical window...
between 350 μm and 10 mm - Array configurations from approximately 150 m to 14 km
- Spatial resolution of 10 milliarcseconds, 10 times better than the Very Large ArrayVery Large ArrayThe Very Large Array is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some fifty miles west of Socorro, New Mexico, USA...
(VLA) and 5 times better than the Hubble Space TelescopeHubble Space TelescopeThe Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared... - The ability to image sources arcminutes to degrees across at one arcsecond resolution
- Velocity resolution under 50 m/s
- Faster and more flexible imaging instrument than the Very Large Array
- Largest and most sensitive instrument in the world at millimetre and sub-millimetre wavelengths
- Point source detection sensitivity 20 times better than the Very Large Array
- Data Reduction system will be CASA (Common Astronomy Software Applications) which is a new software package based on AIPS++AIPS++Astronomical Image Processing System ++ is a software package whose development was started in the early nineties, written almost entirely in C++, and which initial goal was to replace the by then already aging AIPS software...
Project timeline
| Date | Activity |
|---|---|
| 1995 | ESO/NRAO/NAOJ joint site testing with Chile. |
| May 1998 | Start of Phase 1 (Design & Development). |
| June 1999 | European/U.S. Memorandum of Understanding for Design & Development. |
| February 2003 | Final European / North American Agreement, with 50% of funding from ESO, and 50% of funding shared between USA and Canada. |
| April 2003 | Testing of first prototype antenna begins at the ALMA Test Facility (ATF) site in Socorro, New Mexico. |
| November 2003 | Groundbreaking ceremony at ALMA site. |
| September 2004 | European, North American & Japanese draft agreement, with Japan providing new extensions to ALMA. |
| October 2004 | Opening of Joint ALMA office, Santiago, Chile. |
| September 2005 | Taiwan joins the ALMA Project through Japan. |
| July 2006 | European, North American & Japanese amend agreement on the Enhanced ALMA. |
| April 2007 | Arrival of first antenna in Chile. |
| February 2008 | Arrival of the two ALMA transporters in Chile. |
| July 2008 | First antenna movement with a transporter. |
| December 2008 | Acceptance of the first ALMA antenna. |
| May 2009 | First interferometry with two antennas at the Operations Support Facility (OSF). |
| September 2009 | First move of an ALMA antenna to Chajnantor. |
| November 2009 | Phase closure with three antennas at Chajnantor. |
| 2010 | Call for shared-risk Early Science proposals. |
| Second semester 2011 | Start of Early Science. |
| End 2012 | ALMA Inauguration. |
See also
- Atacama Pathfinder Experiment (APEX)Atacama Pathfinder ExperimentThe Atacama Pathfinder Experiment is a radio telescope located at 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert, in northern Chile, 50 kilometers to the east of San Pedro de Atacama. The main dish has a diameter of 12 meters and consists of 264...
, single dish sub-millimetre telescope built on a modified ALMA prototype antenna - Atacama Submillimeter Telescope ExperimentAtacama Submillimeter Telescope ExperimentThe Atacama Submillimeter Telescope Experiment is a 10m antenna built by Mitsubishi Electric as a preprototype for ALMA.The ASTE was deployed to its site on Pampa La Bola, near Cerro Chajnantor and the Llano de Chajnantor Observatory in northern Chile. The antenna shows excellent performance...
- CARMACombined Array for Research in Millimeter-wave AstronomyThe Combined Array for Research in Millimeter-wave Astronomy is an astronomical instrument comprising 23 radio telescopes. These telescopes form an astronomical interferometer where all the signals are combined in a purpose-built computer to produce high-resolution astronomical images.- Location...
a sensitive millimetre-wave array operated by a consortium including Caltech, University of California Berkeley, University of Illinois, University of Maryland and University of Chicago - Cosmic Background ImagerCosmic Background ImagerThe Cosmic Background Imager was a 13-element interferometer perched at an elevation of 5,080 metres at Llano de Chajnantor Observatory in the Chilean Andes...
a 13 element interferometer operating in Llano de Chajnantor since 1999. - IRAM 30 Meter Telescope (Pico VeletaVeleta (Sierra Nevada)Veleta or Pico del Veleta is the third highest peak of the Iberian peninsula and the second highest in the Sierra Nevada. Its height is given variously as , and ....
, SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
), the largest millimetric telescope in the world, operated by IRAM - James Clerk Maxwell TelescopeJames Clerk Maxwell TelescopeThe James Clerk Maxwell Telescope is a submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. Its primary mirror is 15 metres across: it is the largest astronomical telescope that operates in submillimetre wavelengths of the electromagnetic spectrum...
The most sensitive existing sub-millimetre telescope - Plateau de Bure InterferometerPlateau de Bure InterferometerThe Plateau de Bure Interferometer is a six-antenna interferometer on the Plateau de Bure in the French Alps, operated by the Institut de radioastronomie millimétrique....
, one of the most successful existing millimetre-wave arrays, operated by IRAM - List of observatories
External links
- Official ALMA site
- NRAO ALMA site
- UK ALMA site
- ESO ALMA site
- ALMA site by NAOJNational Astronomical Observatory of JapanThe is an astronomical research organisation comprising several facilities in Japan, as well as an observatory in Hawaii. It was established in 1988 as an amalgamation of three existing research organizations - the Tokyo Astronomical Observatory of the University of Tokyo, International Latitude...
- ALMA Antennas Collect First Data, "bbc.co.ukBbc.co.ukBBC Online is the brand name and home for the BBC's UK online service. It is a large network of websites including such high profile sites as BBC News and Sport, the on-demand video and radio services co-branded BBC iPlayer, the pre-school site Cbeebies, and learning services such as Bitesize...
, 17 November 2009. - Huge Observatory in Andes Takes Shape, Space.comSpace.comSpace.com is a space and astronomy news website. Its stories are often syndicated to other media outlets, including CNN, MSNBC, Yahoo!, and USA Today.Space.com was founded by former CNN anchor Lou Dobbs and Rich Zahradnik, in July 1999...
, 7 February 2009.