THE SCIENTIFIC POTENTIAL FOR ASTRONOMY FROM THE ANTARCTIC PLATEAU

Our knowledge of the universe comes from recording the photon and part icle fluxes incident on the Earth from space. We thus require sensitiv e measurement across the entire energy spectrum, using large telescope s with efficient instrumentation located on superb sites. Technologica l advances and engineering constraints are nearing the point where we are recording as many photons arriving at a site as is possible. Major advances in the future will come from improving the quality of the si te. The ultimate site is, of course, beyond the Earth's atmosphere, su ch as on the Moon, but economic limitations prevent our exploiting thi s avenue to the degree that the scientific community desires. Here we describe an alternative, which offers many of the advantages of space for a fraction of the cost: the Antarctic Plateau. Its advantages are manifold: The extreme cold reduces the thermal background in the near- infrared. The low atmospheric water vapour content, by far the driest on the Earth, significantly improves transmission throughout the infra red and millimetre regimes. The tenuous air reduces absorption at all wavelengths. The steadiest air offers superior seeing to any other gro und-based location. It has the clearest air, with the minimum of man-m ade and natural interference, both particulate and electromagnetic, on the Earth. The geographical location contributes in several ways: the high latitude allows continuous monitoring of sources; long north-sou th baselines for VLBI exist, and complete global coverage of some phen omena is possible; the proximity to the South Magnetic Pole extends to lower energy the cosmic ray secondaries that reach the surface; huge quantities of ice are available as pure absorbers of incident particle s such as neutrinos. There are scientific gains to be made across virt ually all areas of observational astronomy: in the near-ultraviolet fr om improved transmission; in the optical from improved seeing; in the near-infrared from reduced background and improved seeing; in the mid- infrared from reduced background and improved transmission; in the far -infrared from improved transmission; in the sub-millimetre and millim etre bands by improved transmission and from the ability to perform in terferometry; in cm-band radio from location as a VLBI site; for cosmi c rays from a greater range of particle energies; for neutrino and gam ma-ray detection by using the ice as an absorber. There are formidable logistical and engineering obstacles to developing an observatory on the Antarctic Plateau. The scientific case for Antarctic astronomy res ts on the merit of programs that could be carried on exclusively on th e Plateau. This document analyses and presents these programs. After c onsideration of the scientific issues, we conclude that the case for t he development of Antarctic astronomy is overwhelming. We propose, the refore, that a program be drawn up to this end. Its ultimate goal will be to construct a major observatory at the premier site on the Antarc tic Plateau, most likely the summit of Dome Argus in the Australian An tarctic Territory. We recognise that such a goal is truly ambitious, a nd that concerted international collaboration will be required to achi eve it. There are several stages that must be successfully completed t o reach this goal, including: Site testing, to quantify our ability to conduct astronomical observations from the Plateau. Development of pr ototype facilities and infrastructure support. A likely project would be the construction of a 60-cm telescope, equipped with optical, infra red and sub-millimetre instrumentation. Construction of intermediate-s ized facilities, capable of achieving significant new science in their own right, but also paving the way to a major facility. Among possibl e options, we suggest that the development of a 2.5-m class telescope, capable of delivering 0.2 arcsec performance across the optical and n ear-infrared wavebands, is particularly germane. The development of a major international facility at the premier site available, built to t he limits of engineering and technological capability, and operable re motely. With its acknowledged expertise in the fields of astronomy and of Antarctic science and exploration, we believe that Australia is we ll positioned to play a major role in the development of what may be o ne of the major international initiatives of the next century.