High-Redshift Active Galactic Nuclei from the 1 Jy Catalog and the Magnification Bias

Abstract

We have found a statistically significant (99.1%) excess of red (O - E > 2) galaxies with photographic magnitudes E < 19.5, O < 21 taken from the APM Sky Catalog around z ~ 1 radio sources from the 1 Jy catalog. The amplitude, scale, and dependence on galaxy colors of the observed overdensity are consistent with their being a result of the magnification bias caused by the weak gravitational lensing of large-scale structures at redshifts z ≈ 0.2-0.4 and are very difficult to explain by such other causes as, e.g., obscuration by dust.