postscript
4 Lensing by clusters...
Abstract...
References...
The Planck Surveyor mission has the potential to detect a very large
sample of gravitationally-lensed galaxies and quasars. The exact size of the
sample is expected to depend on the properties of distant dusty galaxies and
quasars, the cosmological parameters, the observing wavelength and the
sensitivity of the survey. However, several hundred lenses and several hundred
thousand unlensed galaxies are expected at wavelengths of 
and 
. The most promising candidates can be selected for follow-up
observations due to their submillimetre-wave colours determined in the
Planck survey. Observations using FIRST will then determine their
positions with sufficient accuracy for a high-resolution observation using a
ground-based millimetre interferometer array to identify lensed arcs, rings or
multiple images unequivocally. These follow-up observations could be carried
out in several months of dedicated time on these facilities. The scientific
rewards from further investigation of such a large unbiased sample would be
very considerable, and it is difficult to see how such a sample could be
compiled in any other waveband.