## Magnification cross-sections of gravitational lensing by galaxies in general FLRW cosmologies
^{1} Institute of Theoretical Physics, Chinese Academy of
Sciences, Beijing 100080, P.R. China^{2} Beijing Astrophysics Center (BAC) ^{*}, Beijing, 100871, P.R.
China
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.
* BAC is jointly sponsored by The Chinese Academy of Sciences and Peking University
This article contains no SIMBAD objects. ## Contents- 1. Introduction
- 2. Distance and volume measures in general FLRW cosmologies
- 3. Magnification cross-sections of gravitational lensing
- 4. Results and discussions
- Acknowledgements
- References
© European Southern Observatory (ESO) 1998 Online publication: September 17, 1998 |