AMiBA
Encyclopedia
The Yuan-Tseh Lee Array for Microwave Background Anisotropy, also known as the Array for Microwave Background Anisotropy (AMiBA), is a radio telescope
designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect
in clusters of galaxies
. It is located on Mauna Loa
in Hawaii
, at 3,396 m above sea level.
AMiBA is currently configured as a 7-element interferometer atop a hexapod mount. Observations at a wavelength of 3 mm (86–102 GHz
) started in October 2006, and the detections of six clusters by the Sunyaev-Zel'dovich effect were announced in 2008. The telescope will be upgraded to 13 elements by early 2009 and is expandable up to 19 elements. AMiBA is the result of a collaboration between the Academia Sinica
Institute of Astronomy and Astrophysics, the National Taiwan University
and the Australia Telescope National Facility
, and also involves researchers from other universities.
AMiBA is currently configured as a 7-element interferometer, using 0.576 m Cassegrain
dishes mounted on a 6 m carbon fibre hexapod mount. It is located on Mauna Loa, Hawaii, and observes at 3 mm (86–102 GHz
) to minimize foregrounds. The telescope has a retractable shelter, made from seven steel trusses and PVC
fabric.
The receivers are based on Monolithic Microwave Integrated Circuit (MMIC) technology, with low noise amplifiers cooled to 15 K, which have 20 GHz bandwidths and provide 46 dB
of amplification. The signals are mixed with a local oscillator
to reduce their frequency, prior to correlation with an analog correlator. The system temperatures are between 55 and 75 K.
AMiBA started in 2000, with funding for 4 years from the Cosmology and Particle Astrophysics Project of the Taiwan Ministry of Education. A 2-element prototype was set up on Mauna Loa in 2002. Further funding for a second 4 years was provided by the National Science Council
. The mount arrived on site in 2004, and the platform was installed in 2005. The first 7 elements were then installed ("AMiBA7"), and the telescope's first light was in September 2006, observing Jupiter
. The telescope was dedicated in October 2006 to Yuan-Tseh Lee. The array will be upgraded to have thirteen 1.2 m dishes by early 2009 ("AMiBA13"). It is expandable up to 19 elements.
in clusters of galaxies, which has a maximum decrement around 100 GHz. In its initial configuration, it measures up to multipoles of 3,000 with a resolution of around 6 arcminutes. The telescope only observes at night during good weather, using planets for calibration.
Six clusters were imaged in 2007: the Abell clusters 1689
, 1995, 2142
, 2163
, 2261 and 2390, which have redshift
s between 0.091 and 0.322. For the largest and brightest four of these—Abell 1689, 2261, 2142 and 2390—comparisons were made with X-ray and Subaru
weak lensing data to study the cluster layout and radial properties, specifically of the mass profiles and baryon
content. It is predicted that AMiBA with either 13 or 19 elements will be able to detect around 80 clusters per year via the SZ effect.
Institute of Astronomy and Astrophysics, the National Taiwan University
and the Australia Telescope National Facility
. It also involves researchers from the Harvard-Smithsonian Center for Astrophysics
, the National Radio Astronomy Observatory
, the University of Hawaii
, the University of Bristol
, Nottingham Trent University
, the Canadian Institute for Theoretical Astrophysics
and the Carnegie-Mellon University.
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...
designed to observe the cosmic microwave background and the Sunyaev-Zel'dovich effect
Sunyaev-Zel'dovich effect
The Sunyaev–Zel'dovich effect is the result of high energy electrons distorting the cosmic microwave background radiation through inverse Compton scattering, in which the low energy CMB photons receive energy boost during collision with the high energy cluster electrons...
in clusters of galaxies
Galaxy cluster
A galaxy cluster is a compact cluster of galaxies. Basic difference between a galaxy group and a galaxy cluster is that there are many more galaxies in a cluster than in a group. Also, galaxies in a cluster are more compact and have higher velocity dispersion. One of the key features of cluster is...
. It is located on Mauna Loa
Mauna Loa
Mauna Loa is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii in the Pacific Ocean, and the largest on Earth in terms of volume and area covered. It is an active shield volcano, with a volume estimated at approximately , although its peak is about lower than that...
in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, at 3,396 m above sea level.
AMiBA is currently configured as a 7-element interferometer atop a hexapod mount. Observations at a wavelength of 3 mm (86–102 GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....
) started in October 2006, and the detections of six clusters by the Sunyaev-Zel'dovich effect were announced in 2008. The telescope will be upgraded to 13 elements by early 2009 and is expandable up to 19 elements. AMiBA is the result of a collaboration between 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...
Institute of Astronomy and Astrophysics, the National Taiwan University
National Taiwan University
National Taiwan University is a national co-educational university located in Taipei, Republic of China . In Taiwan, it is colloquially known as "Táidà" . Its main campus is set upon 1,086,167 square meters in Taipei's Da'an District. In addition, the university has 6 other campuses in Taiwan,...
and the Australia Telescope National Facility
Australia Telescope National Facility
The Commonwealth Scientific and Industrial Research Organisation 's radio astronomy observatories are collectively known as the Australia Telescope National Facility , with the facility supporting Australia's research in radio astronomy....
, and also involves researchers from other universities.
Design
Cassegrain reflector
The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....
dishes mounted on a 6 m carbon fibre hexapod mount. It is located on Mauna Loa, Hawaii, and observes at 3 mm (86–102 GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....
) to minimize foregrounds. The telescope has a retractable shelter, made from seven steel trusses and PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...
fabric.
The receivers are based on Monolithic Microwave Integrated Circuit (MMIC) technology, with low noise amplifiers cooled to 15 K, which have 20 GHz bandwidths and provide 46 dB
Decibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
of amplification. The signals are mixed with a local oscillator
Local oscillator
A local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer. This process of frequency conversion, also referred to as heterodyning, produces the sum and difference frequencies of the...
to reduce their frequency, prior to correlation with an analog correlator. The system temperatures are between 55 and 75 K.
AMiBA started in 2000, with funding for 4 years from the Cosmology and Particle Astrophysics Project of the Taiwan Ministry of Education. A 2-element prototype was set up on Mauna Loa in 2002. Further funding for a second 4 years was provided by 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:* *...
. The mount arrived on site in 2004, and the platform was installed in 2005. The first 7 elements were then installed ("AMiBA7"), and the telescope's first light was in September 2006, observing Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
. The telescope was dedicated in October 2006 to Yuan-Tseh Lee. The array will be upgraded to have thirteen 1.2 m dishes by early 2009 ("AMiBA13"). It is expandable up to 19 elements.
Observations
The primary goal of AMiBA is to observe both the temperature and polarization anisotropies in the Cosmic Microwave Background at multipoles between 800 and 8,000 (corresponding to between 2 and 20 arcminutes on the sky), as well as observing the thermal Sunyaev-Zel'dovich effectSunyaev-Zel'dovich effect
The Sunyaev–Zel'dovich effect is the result of high energy electrons distorting the cosmic microwave background radiation through inverse Compton scattering, in which the low energy CMB photons receive energy boost during collision with the high energy cluster electrons...
in clusters of galaxies, which has a maximum decrement around 100 GHz. In its initial configuration, it measures up to multipoles of 3,000 with a resolution of around 6 arcminutes. The telescope only observes at night during good weather, using planets for calibration.
Six clusters were imaged in 2007: the Abell clusters 1689
Abell 1689
Abell 1689 is a galaxy cluster in the constellation Virgo. It is one of the biggest and most massive galaxy clusters known and acts as a gravitational lens, distorting the images of galaxies that lie behind it...
, 1995, 2142
Abell 2142
Abell 2142, or A2142, is a huge, X-ray luminous galaxy cluster in the constellation Corona Borealis. It is the result of a still ongoing merger between two galaxy clusters. The combined cluster is six million light years across, contains hundreds of galaxies and enough gas to make a thousand more...
, 2163
Abell 2163
Abell 2163 is one of the richest and most distant clusters of galaxies. Its abell richness class is 2 and position is at a redshift z=0.2. Data from Chandra X-ray Observatory have shown that it is the hottest galaxy cluster in the Abell catalogue...
, 2261 and 2390, which have redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
s between 0.091 and 0.322. For the largest and brightest four of these—Abell 1689, 2261, 2142 and 2390—comparisons were made with X-ray and Subaru
Subaru (telescope)
Subaru Telescope is the 8.2 metre flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades...
weak lensing data to study the cluster layout and radial properties, specifically of the mass profiles and baryon
Baryon
A baryon is a composite particle made up of three quarks . Baryons and mesons belong to the hadron family, which are the quark-based particles...
content. It is predicted that AMiBA with either 13 or 19 elements will be able to detect around 80 clusters per year via the SZ effect.
Collaboration
AMiBA is the result of a collaboration between the Academia SinicaAcademia 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...
Institute of Astronomy and Astrophysics, the National Taiwan University
National Taiwan University
National Taiwan University is a national co-educational university located in Taipei, Republic of China . In Taiwan, it is colloquially known as "Táidà" . Its main campus is set upon 1,086,167 square meters in Taipei's Da'an District. In addition, the university has 6 other campuses in Taiwan,...
and the Australia Telescope National Facility
Australia Telescope National Facility
The Commonwealth Scientific and Industrial Research Organisation 's radio astronomy observatories are collectively known as the Australia Telescope National Facility , with the facility supporting Australia's research in radio astronomy....
. It also involves researchers from the Harvard-Smithsonian Center for Astrophysics
Harvard-Smithsonian Center for Astrophysics
The Harvard–Smithsonian Center for Astrophysics is one of the largest and most diverse astrophysical institutions in the world, where scientists carry out a broad program of research in astronomy, astrophysics, earth and space sciences, and science education...
, 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...
, the University of Hawaii
University of Hawaii
The University of Hawaii System, formally the University of Hawaii and popularly known as UH, is a public, co-educational college and university system that confers associate, bachelor, master, and doctoral degrees through three university campuses, seven community college campuses, an employment...
, the University of Bristol
University of Bristol
The University of Bristol is a public research university located in Bristol, United Kingdom. One of the so-called "red brick" universities, it received its Royal Charter in 1909, although its predecessor institution, University College, Bristol, had been in existence since 1876.The University is...
, Nottingham Trent University
Nottingham Trent University
Nottingham Trent University is a public teaching and research university in Nottingham, United Kingdom. It was founded as a new university in 1992 from the existing Trent Polytechnic , however it can trace its roots back to 1843 with the establishment of the Nottingham Government School of Design...
, the Canadian Institute for Theoretical Astrophysics
Canadian Institute for Theoretical Astrophysics
The Canadian Institute for Theoretical Astrophysics is a national research institute funded by the Natural Sciences and Engineering Research Council, located at the University of Toronto in Toronto, Ontario, Canada...
and the Carnegie-Mellon University.