Brazil and Argentina Begin Construction of Radio Astronomy Observatory

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It follows an article published day (08/13) in the english website of the Agência FAPESP noting that Brazil and Argentina begin construction of Radio Astronomy Observatory.

Duda Falcão

Articles

Brazil and Argentina Begin Construction
of Radio Astronomy Observatory

By Elton Alisson
August 13, 2014

(Photo: public domain image
Radio telescope will be installed in the
Argentine Andes at a height of nearly
5,000 meters. Project is funded by FAPESP and
the Ministry of Science and Technology of Argentina.
Agência FAPESP – Unlike in soccer, there is no sign of rivalry between Brazil and Argentina in regard to astronomy. The two countries are joining efforts over the coming years to install a 12-meter-diameter parabolic antenna radio telescope in the Argentine Andes, near the Chilean border, at a height of 4,825 meters above sea level.

Scheduled to begin operation in 2017, the astronomical observation equipment is part of the project known as LLAMA - Long Latin American Millimetric Array, and a play on the indigenous Quechuan word for the ruminant found in South America.The project includes support by FAPESP, the Ministry of Science, Technology and Productive Technology of Argentina, and the University of São Paulo (USP) through an agreement among the institutions that stipulates the conditions for its implementation.

The project is being led by professor Jacques Raymond Daniel Lépine of the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) at USP and includes participation by researchers of the Argentine Institute of Radio astronomy (IAR).

“FAPESP will provide [the equivalent in reais] US$9.2 million for construction of the radio telescope, and in return, the Argentine ministry will provide resources to a similar value to build the observatory and complete the infrastructure projects related to preparing the land where the radio telescope will be built,” Lépine told Agência FAPESP.

The radio telescope will be installed on a mountain in the Altos de Chorriles, in the Argentine Province of Salta (1,600 kilometers (km) northeast of Buenos Aires). It will operate at millimeter and submillimeter wavelengths to capture radiation in the infrared to radio wave range of the electromagnetic spectrum at frequencies between 100 and 900 gigahertz (Ghz).

The equipment will permit studies to be carried out in practically all areas of astronomy, including the evolution of the Universe, black holes, and the formation of galaxies, stars and the interstellar medium.

“There are many objects and astronomic regions that can be observed at frequencies between 100 and 1,000 Ghz but that are not visible below 100 Ghz. Although there are several radio telescopes that operate at frequencies below 100 Ghz, there are very few that operate in the range between 100 and 1,000 Ghz,” Lépine said.

Among the objects and astronomical regions that will be observable by the LLAMA are cold clouds of gas and dust where new stars are forming, as occurs in many places in the Milky Way.

With temperatures of only a few degrees above absolute zero, these cold clouds in the interstellar medium form “blackout curtains” that make regions where stars and galaxies form dark and opaque in the visible light range of the electromagnetic spectrum captured by optical telescopes.

Using millimeter and submillimeter radiation captured by the LLAMA radio telescope, it will be possible to peer through these cold clouds of gas and dust to see what is behind them and to observe objects with even lower brilliance, as well as to explore details about the sources of radiation, Lépine explained.

“Radio waves at millimeter and submillimeter radio frequencies are absorbed by the atmosphere’s water vapor. That’s why radio telescopes need to be installed at high altitudes with low humidity,” he explained.

Near ALMA

The LLAMA radio telescope will be one of the world’s highest astronomical observatories, along with the ALMA (Atacama Large Millimeter/Submillimeter Array), located on the Chajnantor Plateau 5,000 meters above sea level in the Atacama Desert of Chile, and with the Atacama Pathfinder Experiment Telescope (Apex), the highest observatory on Earth, situated 5,100 meters above sea level (also on the Chajnantor Plateau) and a precursor to the ALMA.

The LLAMA radio telescope will be located 150 kilometers (km) in a straight line from the ALMA and will also be built by one of the companies that supplied half of the 66 high-precision radio antennas – also 12 meters in diameter, operating at millimeter and submillimeter wavelengths – to the Chilean observatory, considered one of the world’s largest radio astronomy projects under way.

The similarities between the LLAMA antenna and those at the Chilean observatory – financed by member countries of the European Space Observatory (ESO) in addition to the United States, Canada, Japan and Taiwan – and the proximity of the two observatories will allow them to operate together in interferometric mode, Lépine explained.

“The ALMA antennas function as an interferometer, with all of the antennas interconnected and operating together. The signals captured by the 66 antennas are collected and combined to produce high-resolution images of the observed regions, similar to those that may be obtained with a single 16-km-diameter telescope,” he said.

According to the IAG-USP professor, the positioning of the LLAMA antenna at a distance of 150 km from the ALMA will allow it to operate as another of the Chilean observatory’s antennas.

Because it will be located at a greater distance from the 66 ALMA antennas, the LLAMA radio telescope will be able to produce images of the Universe with a much larger angular resolution of the image, Lépine notes. “The larger the spacing between the antennas, the higher the image definition,” he said.

Initially, however, astronomical observations by the LLAMA will be carried out in “single antenna” mode. The idea is to start by conducting simple astronomical observations using a single antenna that can then contribute to observations made in interferometric mode.

“There is a lot of astronomical science that can be done with a single antenna. It can be used to map the regions of the Universe in order to identify potential targets to be observed later using the ALMA,” Lépine noted.

The LLAMA could also help Brazilian and Argentine astronomers become certified in the use of the ALMA and thus have better opportunities to compete for observation time on the Chilean observatory radio telescope.

Because there is stiff international competition for observation time on the ALMA radio telescope, astronomers who are trying to use the Chilean observatory for their research must have some experience in high-frequency radio astronomy and knowledge about the region of the Universe they would like to observe.

The LLAMA will enable Brazilian and Argentine astronomers to gain more high-frequency radio astronomy experience and to develop proposals for observations using the ALMA, Lépine said.

“Furthermore, they can also use the LLAMA radio telescope to observe in advance those regions of the Universe they would like to explore with the ALMA and better substantiate their proposals for observation,” he noted.

Over one thousand proposals were received during the first call for projects launched by the Chilean observatory, which was inaugurated in March 2013 after 15 years of planning and construction at a cost of US$1.4 billion.

One of the research projects considered was submitted by Prof. Zulema Abraham of IAG-USP, one of the principal investigators in the FAPESP-funded thematic project to build the LLAMA.

“Astronomers from ALMA are interested in collaborating with the LLAMA knowing that if the antennas of the two observatories operate in interferometric mode, the resolution will be much better,” Lépine opined.

Latin Network of Radio Telescopes

According to Lépine, the intention is that the LLAMA will be the seed for establishing a Latin American network of radio telescopes, situated in different locations and countries of the region, operating in very-long-baseline interferometry (VLBI) mode.

The northern hemisphere has a series of radio telescope networks established by regions such as the United States and Europe. The Unites States hosts the Very Large Array (VLA), which has 27 interconnected 25-m-diameter antennas stationed along a maximum range of 21 kilometers. Europe operates the European VLBI Network (EVN), which has antennas scattered throughout the European continent and South Africa. The southern hemisphere does not yet have a radio telescope network.

Through ALMA and projects such as the LLAMA, in addition to other recent radio telescope building initiatives in Latin America – such as the 43-Ghz-frequency 30-m-diameter device to be installed in Argentina by China and radio telescopes such as the Itapetinga in São Paulo, and another in Peru – it will be possible to begin to establish a network of radio telescopes to explore regions of the Universe that are best observed from the southern hemisphere. Among these is the center of the galaxy, which is situated below the Equator, Lépine explained.

“There is enormous potential for establishing a network of radio telescopes that operate by interferometry in Latin America, and there are groups of radio astronomy researchers who plan to install new antennas in the region in the future, at distances of the order of hundreds of kilometers, to constitute a network,” Lépine said.

“The LLAMA could serve as a bridge for science and technology integration in radio astronomy in Latin America,” the researcher stated.


Source: English WebSite of the Agência FAPESP

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