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

We calculate the angular cross-correlation function between background QSOsand foreground galaxies induced by the weak lensing effect of large-scalestructures. Results are given for arbitrary Friedmann-Lemaitre cosmologies. Thenon-linear growth of density perturbations is included. Compared to the lineargrowth, the non-linear growth increases the correlation amplitude by about anorder of magnitude in an Einstein-de Sitter universe, and by even more forlower Omega_0. The dependence of the correlation amplitude on the cosmologicalparameters strongly depends on the normalization of the power spectrum. TheQSO-galaxy cross-correlation function is most sensitive to density structureson scales in the range (1-10) Mpc/h, where the normalization of the powerspectrum to the observed cluster abundance appears most appropriate. In thatcase, the correlation strength changes by less than a factor of <~ 2 whenOmega_0 varies between 0.3 and 1, quite independent of the value ofOmega_Lambda. For Omega_0 <~ 0.3, the correlation strength increases withdecreasing Omega_0, and it scales approximately linearly with the Hubbleconstant h.Comment: revised version, accepted by MNRA