QSO-galaxy correlations induced by weak lensing in arbitrary Friedmann-Lemaître cosmologies

We calculate the angular cross-correlation function between background QSOs and fore­ ground galaxies induced by the weak lensing effect oflarge-scale structures. Results are given for arbitrary Friedmann-Lemaftre cosmologies. The non-linear growth of density perturba­ tions is included. Compared with the linear growth, the non-linear growth increases the correlation amplitude by about an order of magnitude in an Einstein-de Sitter universe, and by even more for lower 0 0, The dependence of the correlation amplitude on the cosmological parameters strongly depends on the normalization of the power spectrum. The QSO-galaxy cross-correlation function is most sensitive to density structures on scales in the range (1 - 1O)h-1 Mpc, where the normalization of the power spectrum to the observed cluster abundance appears most appropriate. In that case, the correlation strength changes by less than a factor of::52 when 0 0 varies between 0.3 and 1, quite independent of the value of 0A' For 0 0 ::5 0.3, the correlation strength increases with decreasing 0 0, and it scales approximately linearly with the Hubble constant h.