There is controversy about the measurement of statistical associations between bright quasars and faint, presumably foreground galaxies. We look at the distribution of galaxies around an unbiased sample of 64 bright, moderate-redshift quasars using a new statistic based on the separation of the quasar and its nearest-neighbour galaxy. We find a significant excess of close neighbours at separations less than about 10 arcsec which we attribute to the magnification by gravitational lensing of quasars which would otherwise be too faint to be included in our sample. About one quarter to one third of the quasars are so affected, although the allowed error in this fraction is large.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1995
- METHODS: STATISTICAL;
- QUASARS: GENERAL;
- GRAVITATIONAL LENSING;
- uuencoded Postscript file (including figures and tables), SUSSEX-AST 94/8-4