AST 95-29274 PI: Gerard Luppino Wide Field Observations of Weak Gravitational Lensing Using the UH 8192 x 8192 CCD Mosaic Camera The proposed observational funding is aimed at mapping dark matter on cluster and larger scales using weak gravitational lensing. The program will exploit unique access to an instrument built specifically for lensing studies: the new UH 8192x8192 CCD mosaic camera.. The mosaic is a close-packed 4x2 array of CCDs with 15 um pixels providing a 0.47 deg wide field of view. The observations will concentrate on two areas. The first is to obtain wide field images of clusters of galaxies spanning redshifts between 0.1 and 1, thus probing cluster dark matter profiles at large radii. For two clusters with giant arcs, for which an existing HST image is available, the mass profile reconstruction will be extended into the core, providing evidence to help distinguish between various dark matter models. The second observational program is a deep survey in two colors, V and I, covering a 10 degree-squared area, to search for weak lensing by the large scale structure of the universe, and directly measure the mass power spectrum P(k). Such searches have been severely limited by the narrow fields of view available until now. This instrument should measure positions, shapes, magnitudes and colors of ~1-2 million galaxies in three years.
