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B. Jain (JHU), U. Seljak (CfA), S. White (MPA)
Large-scale structure in the universe shears and magnifies the images of distant galaxies. Measurement of this weak lensing effect on randomly selected, degree sized fields promises to be a powerful tool for mapping large-scale structure in the universe. We have developed analytical and numerical methods for linking theoretical predictions of shear statistics with observational data. Ray tracing simulations, coupled with an ensemble of high resolution N-body simulations of the dark matter distribution, have been used to generate maps of the shear and magnification fields that span the range of scales accessible to weak lensing observations. These maps have been used to compute the power spectrum, spatial moments, and the probability distribution function of the shear and magnification. Sample sizes required to measure the power spectrum from noisy data have been estimated. The skewness of the probability distribution function can be used to estimate Omega. Our results suggest that with a total survey area of order 10 square degrees the shear power spectrum can be accurately measured on scales of 1-10 Mpc , and Omega determined to within about 0.1. Comparison of the shear field with galaxy surveys will provide a direct measure of the biasing of galaxies.
The author(s) of this abstract have provided an email address for comments about the abstract: bjain@pha.jhu.edu