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Session 62 - Workshop on the Future of Antarctic Astrophysics - II.
Topical, Oral session, Wednesday, June 10
The advent of a sensitive new submillimeter-wave instrument, the SCUBA bolometer array receiver at the James Clerk Maxwell Telescope, has allowed the first deep images of the distant Universe to be made in this exciting waveband. Galaxies are visible in the submillimeter waveband due to the emission of reprocessed light by interstellar dust grains. Hence, observations in this waveband are complementary to those in the optical. The K-corrections for faint galaxies are large and negative in the submillimeter waveband, and so the selection function of a submillimeter-wave survey is expected to both be flat and extend out to very large redshifts. This has two advantages for a survey of galaxy clusters: i) the lensed images of distant background galaxies are expected to be detectable out to large redshifts and to experience very large magnification biases as compared with optically-selected samples; ii) the flux densities of cluster member galaxies are expected to be smaller than those of the lensed images. The most prominent sources in sensitive submillimeter-wave observations should hence be lensed images of background galaxies. Last summer, Ian Smail, Rob Ivison, Andrew Blain and Jean-Paul Kneib used SCUBA to obtain the first submillimeter-wave images of clusters. The results provided the first observational data on: submillimeter source counts; source confusion expected in future surveys; and the processes of formation and evolution of dusty galaxies. The capability and number of submillimeter-wave telescopes is going to grow very substantially in the next few years, and the sample of about 30 lensed galaxies detected by Smail et al. will be expanded greatly. The excellent atmospheric transmission and low ambient temperature in Antarctica makes it an ideal site for progress in submillimeter cosmology. I discuss what we have learned from the very first surveys of lensing clusters, and describe the exciting prospects for the future.
Program listing for Wednesday