Do Lensing Statistics Rule Out a Cosmological Constant?
We present new calculations of gravitational lensing statistics in view of recent revisions in our knowledge of the luminosity function and internal velocity dispersion of E/S0 galaxies that work as effective lenses for background high-redshift QSOs. We show that the theoretical prediction of the lensing statistics is much smaller than previously expected. In sharp contrast to earlier statistics supporting an Ω0 = 1 universe, the small lensing probability reported from the Hubble Space Telescope (HST) Snapshot Lens Survey is in best agreement with a low-density, flat universe with Ω0 ~= 0.2 and Ω0 + λ0 = 1. The age of this universe, combined with the HST measurement of a high value for the Hubble constant H0, can be reconciled with the age of the oldest globular clusters in the Milky Way.
The Astrophysical Journal
- Pub Date:
- November 1997
- Cosmology: Theory;
- Galaxies: General;
- Cosmology: Gravitational Lensing