Gravitational Lensing Statistics Based on a Large Sample of Highly Luminous Quasars
Abstract
Results on gravitational lensing statistics applied to a sample of 469 highly luminous quasars are reported. The objects were directly imaged, either from the ground (ESO, CFH) under optimal seeing conditions, or using the Hubble Space Telescope. We have derived values for the effectiveness parameter F of galaxies, modeled by means of singular isothermal spheres, to produce macrolensed images of distant quasars, and upper limits on the density parameter {OMEGA}_L_ of compact objects with masses ~10^10^ - 10^12^ M_sun_. Adopting H_0_ = 50 km/s/Mpc, {OMEGA}_0_= 1 and λ = 0, we find that at the 99.7% confidence level, 0.005 < F < 0.478 and that {OMEGA}_L_ < 0.02. A critical discussion of these results is presented. Finally, comparing the efficiencies of ground-based and space instruments used to search for gravitational lens systems among highly luminous quasars, we conclude that for the near future, ground based direct imaging characterized by a good dynamical range still constitutes the best observational strategy.
- Publication:
-
The Astronomical Journal
- Pub Date:
- June 1993
- DOI:
- 10.1086/116584
- Bibcode:
- 1993AJ....105.2064S
- Keywords:
-
- Gravitational Lenses;
- Quasars;
- Cosmology;
- Galaxies;
- Astrophysics;
- QUASARS: GENERAL;
- GRAVITATIONAL LENSING