A weak lensing detection of the cosmological distance-redshift relation behind three massive clusters.

The amplitude of weak lensing should increase with source distance, rising steeply behind a lens and saturating at high redshift, providing a model-independent means of measuring cosmic geometry. We measure the amplitude of weak lensing with redshift for three massive clusters, A370 (), ZwCl0024+17 () and RXJ134711 (), using deep, three-colour Subaru imaging. We define the depth of lensed populations with reference to the COSMOS and GOODS fields, providing a consistency check of photo- z estimates over a wide range of redshift and magnitude. The predicted distance-redshift relation is followed well for the deepest data set, A370, for a wide range of cosmologies, and is consistent with less accurate data for the other two clusters. Scaling this result to a new survey of massive clusters should provide a useful cosmological constraint on , complementing existing techniques, with distance measurements covering the untested redshift range, . [ABSTRACT FROM AUTHOR]