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| CNRS Networks cnrs I international w 34 magazine by Mathieu Grousson ALMA (Atacama Large Millimeter/ submillimeter Array), the largest telescope ever designed, was inaugurated on March 13. Towering above 5000 meters in the heart of the Chilean Andes, its 57 mobile antennas (which will total 66 when completed this summer) are relentlessly scanning the sky. Scattered over an area of 200 km2, with diameters of 7 and 12 meters, these antennas operate in perfect synchronicity. The instrument, built by a consortium gathering the 14 countries of the European Southern Observatory (ESO), along with the US, Canada, Japan, and Taiwan, can observe with unparalleled precision phenomena such as the birth of stars and planetary systems, and the formation of the very earliest galaxies. “ALMA is genuinely revolutionary in terms of sensitivity and resolution,” explains Laurent Vigroux, director of the IAP.1 Once the antennas are placed in their compact configuration, the instrument— whose total area covers 7 km2— will be nearly ten times more sensitive than today’s most powerful radio telescope, the Plateau de Bure Interferometer, located in the French Alps. In its extended configuration, which calls for antennas located some 16 kilometers away, image resolution will reach a staggering 0.01 arcsecond, as compared to 0.3 for the Plateau de Bure instrument. For astrophysicists, ALMA opens up an extraordinary window into the far infrared (millimeter and submillimeter wavelengths), the part of the electromagnetic spectrum where the universe’s cold phenomena can be observed. This exceptional facility will also enable scientists to explore the chemistry of the interstellar medium, where complex organic molecules are formed, including the precursors of amino acids—the basic building blocks of proteins. In addition, the radio telescope array will prove invaluable for detecting the very earliest galaxies, which appeared when the universe was a mere billion years old. It will also have the unrivaled ability to see through the clouds of gas and dust—impenetrable to visible light—where stars and planetary systems are born. Using only 16 of the 57 antennas already set up on the plateau, astrophysicists have already succeeded in drawing up the most accurate map ever obtained of gas dynamics within a galaxy. Specialists have also quantified the gas content, age, and rate of star formation for some 20 galaxies, observed as they were less than a billion years after the Big Bang. “The ejection of cold matter from ageing stars has also been the object of interesting findings,” Vigroux points out. “It is still difficult to imagine ALMA’s potential for discovery. All we know is that it's quite spectacular.” 01. Institut d’astrophysique de Paris (CNRS / UPMC). Contact i nformation: IAP, Paris. Laurent Vigroux > vigroux@iap.fr FRANCE JOINS THE E-ELT GIANT TELESCOPE PROJECT w At the Council of the European Southern Observatory (ESO) on December 4, 2012, France voted to participate in the European Extremely Large Telescope (E-ELT) project. “This is a very important step, because the project isn't feasible without France,” explains Laurent Vigroux, director of the Paris Institute of Astrophysics (IAP). Construction of the telescope, which will boast the world’s largest mirror (39 m in diameter) is nonetheless still awaiting Brazil’s adhesion to the ESO. The answer should be known at the organization’s next Council meeting in June. If the project is confirmed, the astronomical revolution of the coming decade will truly be underway. 01 Astrophysics ALMA, the world’s most powerful radio telescope, will enable astrophysicists to undertake research hitherto deemed impossible. Stars in ALMA’s Eyes © ALMA (ESO/NAOJ/NRAO)/M. Maerc ker e t al . 02 01 ALMA , once complete, will be made up of an array of 66 mobile antennas. 02 The radio telescope has already begun providing images. Here a novel spiral structure in the matter surrounding the ancient star R Sculptoris. © ALMA (ESO/NAOJ/NRAO)/C. Padilla


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