Weak lensing predictions at intermediate scales |
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| Authors: | Ludovic Van Waerbeke Takashi Hamana † Román Scoccimarro Stephane Colombi Francis Bernardeau |
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| Institution: | Canadian Institute for Theoretical Astrophysics, 60 St George Street, Toronto, M5S 3H8, Canada;Institut d'Astrophysique de Paris, 98 bis Bld Arago, 75014 Paris, France;Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA;Numerical Investigations in Cosmology (NIC), CNRS, France;Service de Physique Théorique. CE de Saclay, 91191 Gif sur Yvette Cedex, France |
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| Abstract: | As pointed out in previous studies, the measurement of the skewness of the convergence field κ will be useful in breaking the degeneracy among the cosmological parameters constrained from weak lensing observations. The combination of shot noise and finite survey volume implies that such a measurement is likely to be performed in a range of intermediate scales (0.5 to 20 arcmin) where neither perturbation theory nor the hierarchical ansatz applies. Here we explore the behaviour of the skewness of κ at these intermediate scales, based on results for the non-linear evolution of the mass bispectrum. We combined different ray-tracing simulations to test our predictions, and we find that our calculations describe accurately the transition from the weakly non-linear to the strongly non-linear regime. We show that the single lens-plane approximation remains accurate even in the non-linear regime, and we explicitly calculate the corrections to this approximation. We also discuss the prospects of measuring the skewness in upcoming weak lensing surveys. |
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| Keywords: | gravitational lensing large-scale structure of Universe |
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