Statistics of weak lensing at small angular scales: analytical predictions for lower order moments |
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| Authors: | Dipak Munshi † Bhuvnesh Jain |
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| Institution: | Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str.1, D-85740 Garching, Germany;Johns Hopkins University, Department of Physics, Baltimore, MD 21218, USA |
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| Abstract: | Weak lensing surveys are expected to provide direct measurements of the statistics of the projected dark matter distribution. Most analytical studies of weak lensing statistics have been limited to quasi-linear scales as they relied on perturbative calculations. On the other hand, observational surveys are likely to probe angular scales less than 10 arcmin, for which the relevant physical length-scales are in the non-linear regime of gravitational clustering. We use the hierarchical ansatz to compute the multipoint statistics of the weak lensing convergence for these small smoothing angles. We predict the multipoint cumulants and cumulant correlators up to fourth order and compare our results with high-resolution ray-tracing simulations. Averaging over a large number of simulation realizations for four different cosmological models, we find close agreement with the analytical calculations. In combination with our work on the probability distribution function, these results provide accurate analytical models for the full range of weak lensing statistics. The models allow for a detailed exploration of cosmological parameter space and of the dependence on angular scale and the redshift distribution of source galaxies. We compute the dependence of the higher moments of the convergence on the parameters Ω and Λ. |
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| Keywords: | gravitational lensing methods: analytical cosmology: theory large-scale structure of Universe |
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