Cosmic shear surveys

Abstract

Gravitational weak shear produced by large-scale structures of the universe induces a correlated ellipticity distribution of distant galaxies. The amplitude and evolution with angular scale of the signal depend on cosmological models and can be inverted in order to constrain the power spectrum and the cosmological parameters. We present our recent analysis of 50 uncorrelated VLT fields and the very first constrains on ($\Omega_m,\sigma_8$) and the nature of primordial fluctuations based on the join analysis of present-day cosmic shear surveys.Comment: Latex, 7 pages. To appear in the ESO Proceedings ``Deep Fields'', Garching Oct 9-12, 200