Magnification cross-sections of gravitational lensing by galaxies in general FLRW cosmologies
Received 7 April 1998 / Accepted 30 June 1998
For a wide variety of cosmological models characterized by the cosmic mass density and the normalized cosmological constant , we derive an analytic expression for the estimate of magnification cross-sections by an ensemble of isothermal spheres as models of galactic mass distributions. This provides a simple approach to demonstrate how the lensing probability by galaxies depends on the cosmological parameters. An immediate consequence is that, while a non-zero cosmological constant indeed leads to a significant increase of the lensing probability as it has been shown in the literature, only a small fraction of sky to can be moderately () lensed by galaxies even in a -dominated flat universe. Therefore, whether or not there is a nonzero cosmological constant, it is unlikely that the overall quasar counts have been seriously contaminated by the presence of galactic lenses.
Key words: gravitational lensing galaxies: general
Send offprint requests to: Z.-H. Zhu 1
This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1998
Online publication: September 17, 1998