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Advancing European submillimetre/terahertz astronomy in Antarctica

Final Activity Report Summary - AESTAA (Advancing European Submillimetre/Terahertz Astronomy in Antarctica)

Matter in the universe is continuously recycled: Stars return much of their mass to the galaxy in the form of gas and dust clouds (the Interstellar Medium), and these clouds then form new generations of stars and planets. The most mysterious stages of this cycle are the condensation of the warm gas into cold dense clouds and the collapse of those clouds to form new stars. In order to understand these processes, we need to observe the clouds at wavelengths of a few tenths of a millimetre. This wavelength range is called submillimetre-wave or Terahertz radiation, and it is in this part of the electromagnetic spectrum that these clouds emit most energy.

Unfortunately, Terahertz radiation is strongly absorbed by the Earth's atmosphere, making it very difficult to observe. Satellite observatories overcome this limitation, but they are generally small, slow to develop, and very expensive. A complementary approach is to build telescopes on the ground where the atmosphere is unusually transparent to Terahertz radiation, at very high, dry sites, such as the Atacama Desert in South America. But the driest atmosphere in the world is found above the peaks (or 'domes') of the Antarctic ice cap, where the air is so cold that it can hold very little water vapour.

AESTAA is a project to develop submillimetre-wave and Terahertz Astronomy at these sites, collaborating with international teams. We have worked with European colleagues to learn how to build Terahertz telescopes at places like Concordia, the Franco-Italian station at Dome C, and we are partners in the HEAT project to place a fully-automated Terahertz telescope at Dome A, where there is no permanent human presence. The first stage in HEAT (a collaboration between European countries, China, Australia, and the USA) is a pathfinder instrument ('preHEAT') on the fully-robotic PLATO site-testing observatory. PLATO and preHEAT were deployed to Antarctica at the beginning of 2008, and operated continuously for 204 days - a record for such a large and complex automated system in Antarctica. PreHEAT monitored the atmospheric transparency in the Terahertz regime during this time, and preliminary analysis shows that Dome A is an exceptional site to do Terahertz astrophysics. Although the Antarctic Plateau is a challenging environment in which to operate, the deployment of Terahertz observatories there holds out the promise of a deeper understanding of the origins of stars and planets.