Philip Yock
, PASA, 17 (1), 35.
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Gravitational Microlensing from the Antarctic
To realise the full potential of the gravitational microlensing technique it is necessary to monitor millions of stars with good photometric accuracy at a sampling rate of a few observations per hour in several passbands. The existing network of southern survey and follow-up telescopes (MACHO, OGLE, EROS, GMAN, PLANET, MPS and MOA) do a relatively good job of monitoring the Galactic bulge and the Magellanic Clouds. Further improvement may be expected to occur soon as new image subtraction techniques with better photometric accuracy are refined and incorporated (Alard & Lupton 1998; Alard 1999). A quantum leap might be realised with a telescope at the Antarctic. The idea has been raised before (Sahu 1998; Muraki et al. 1999). Such a telescope could monitor southern fields essentially continuously, thus avoiding the not inconsiderable difficulties associated with combining data from different groups using different telescopes and different passbands, and working under different seeing conditions. Losses of data due to inclement weather would also be less serious. To monitor the complete peak of a typical high magnification event from the Antarctic would require good weather for a few days in one location only. Presently, good weather is required simultaneously in Chile, in Australasia and in South Africa.2 By observing in the infrared, and taking advantage of the exceptionally dry conditions at the Antarctic, one could extend the present measurements to include the centre of the Galaxy. Gould has pointed out this would increase the total event rate (Gould 1995b). A 2-m class telescope would be the preferred option to extend the current observations being made with 1-m class instruments. US and Australian groups have already made considerable progress towards the development of the Antarctic for infrared astronomy (Burton 1996). Observations have been made from the South Pole which confirm its excellent characteristics at infrared wavelengths, and site-testing is in progress at Dome-C (see Figure 12) which promises to be even superior (Burton 1999). In view of the above, Dome-C would seem to be a promising site for future development of gravitational microlensing.Next Section: Conclusions
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