Publication : t00/155

Weak Lensing Predictions at Intermediate Scales

Van Waerbeke L. (Canadian Institute for Theoretical Astrophysics (CITA), University of Toronto, 60 St. George Street, Toronto, M5S 3H8 Ontario, CANADA)
Hamana T. (Institut d\'Astrophysique de Paris (IAP-CNRS), 98 bis Bld Arago, F-75014 Paris, FRANCE)
Scoccimarro R. (Institute for Advanced Study (IAS), Einstein Drive, Princeton, New Jersey 08540, USA)
Colombi S. (Institut d\'Astrophysique de Paris (IAP-CNRS), 98 bis Bld Arago, F-75014 Paris, FRANCE)
Bernardeau F. (CEA, DSM, SPhT (Service de Physique Théorique), F-91191 Gif-sur-Yvette, FRANCE)
As pointed out in previous studies, the measurement of the skewness of the convergence field $\kappa$ 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 done in a range of intermediate scales ($0.5'$ to $20'$) where neither perturbation theory nor the hierarchical ansatz apply. Here we explore the behavior of the skewness of $\kappa$ 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.
Année de publication : 2001
Revue : Mon. Not. R. Astron. Soc. 322 918-926 (2001)
Preprint : arXiv:astro-ph/0009426
Keywords : cosmology, gravitational lensing, large-scale structure of the universe
Langue : Anglais


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