Maximal Lens Bounds on QSO-Galaxy Association
Abstract
I derive the maximal possible enhancement of QSO number counts that can be produced by any ensemble of lenses which conserve brightness and in which the magnification probability distribution in negligibly correlated with the intrinsic QSO flux. This bound is applied to the Webster et al. QSO-galaxy association sample, assuming the Boyle et al. number-magnitude relation for the QSOs unaffected by lenses. The maximal expectation is enhancement by factor E < 4.0, whereas the Webster et al. enhancement is by factor E = 6.0. Usual gravitational lens models are expected to produce E ~ 2-3, for the Webster et al. sampling conditions. Aside from the possibilities that an unusual statistical fluctuation or observational errors may be involved, Webster et al. may have discovered that the background QSOs are appreciably affected by lensing.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1989
- DOI:
- 10.1086/185443
- Bibcode:
- 1989ApJ...341L...1K
- Keywords:
-
- Computational Astrophysics;
- Galaxies;
- Gravitational Lenses;
- Quasars;
- Background Radiation;
- Brightness Distribution;
- Image Processing;
- Astrophysics;
- ANALYTICAL METHODS;
- GALAXIES: GENERAL;
- GRAVITATIONAL LENSES;
- QUASARS