Stellar embryos are very cold: Embedded in dusty cocoons, they emit the bulk of their energy around 100 microns. This is why observations in the far-infrared/submillimetre-wave range are required to unveil the birth and early evolution of stars and their planetary systems. At Dome C, it is possible to observe at these wavelengths for long periods of time, allowing astronomers to study star-forming regions in the Magellanic Clouds (mentioned above) and the cosmic infrared background of distant galaxies. These distant galaxies are more luminous in the infrared than the closest galaxies are, possibly because they form stars more efficiently. Such observations are only possible when the the precipitable water vapor (pwv) drops below 0.5 mm, which occurs less than 30% of wintertime at the ALMA site ? the telescope array project currently under construction on the Chajnantor plateau in Chile. However at Dome C, the pwv would be lower than 0.2 mm between 25 and 50% of the time over the year. Dome C is thus an exceptional site for observations in the far-infrared/submillimetre-wave range.
? V. Minier (CEA) Observations in the submillimeter-wave range accessible from Dome C could reveal original and very important informations on the young and cold Universe, on evolution of galaxies and on the formation of stars and planets. This is why scientists think about the installation of a 20-meter antenna at Dome C or maybe an interferometric array made of such antennas.
Several preliminary steps are required before fully implementing a submillimetre-wave telescope at Dome C. Initially, small infrared and millimetre-wave telescopes already on-site (the 0.8m IRAIT and 2.6m COCHISE) will be equipped with submillimetre-wave detectors. These systems will definitively assess the site quality at these wavelengths and will act as testbeds to gain technological know-how for future large projects under polar conditions (unmanned telescope control, mirror technology at temperatures lower than -70 ?C, use of alternative energies...). Meanwhile, 12m-diameter ALMA-type antennas are under construction as well as the 10m SPT instrument at the South Pole. By exploiting the expertise gained from the construction of these two instruments, it will become possible to implement an ALMA-type antenna optimized for polar conditions, and in the longer term to consider a submillimetre-wave antenna array complementary to ALMA. This would be the first instrument in the world able to carry out observations with high angular resolution in the submillimetre-wave range, which could observe the very first phases of star formation.
? T.A. Rector and B.A. Wolpa - University of Alaska, NRAO/AUI/NSF and NOAO/AURA/NSF
Located at 7000 light-years, the Eagle Nebula is a real star-forming region inside our own galaxy. With observations in the submillimeter-wave domain, the astronomers will be able to study these phenomena in other galaxies.
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