COSMOLOGICAL PARAMETERS FROM ANGULAR-CORRELATIONS BETWEEN QSOS AND GALAXIES

The angular two-point correlation function between background QSOs and foreground galaxies induced by gravitational lensing is derived. It i s shown that the shape of this correlation function depends sensitivel y on the spectrum of the density fluctuations in the Universe, thus pr oviding a possibility to distinguish between different models for the spectrum. Using numerical large-scale structure simulations, I estimat e that the QSO-galaxy correlation function can be measured from galaxy counts down to similar or equal to 21(st) ... 22(nd) magnitude in fie lds with radius less than or similar to 25' around 50 ... 100 QSOs wit h redshift z greater than or equal to 1. Since the QSO-galaxy correlat ion function is proportional to (-a -1)b, where b is the biasing facto r of galaxy formation and a is the effective slope of the QSO number c ounts, steep number counts are favorable for this kind of analysis. I show that a = -4 ... -5 can be achieved with the 1-Jansky sample of ra dio-loud QSOs when the double-waveband magnification bias is employed. Moreover, the cross-correlation analysis allows to determine the gala xy-formation bias factor b.