Using the 6dF Galaxy Redshift Survey to Detect Gravitationally-lensed Quasars

Abstract

It is possible to detect gravitationally-lensed quasars spectroscopically if the spectra obtained during galaxy surveys are searched for the presence of quasar emission lines. The up-coming 6 degree Field (6dF) redshift survey on the United Kingdom Schmidt Telescope will involve obtaining ~10⁵ spectra of near-infrared selected galaxies to a magnitude limit of K = 13. Applying previously developed techniques implies that at least one lens should be discovered in the 6dF survey, but that as many as ten could be found if quasars typically have B_J – K ~ 8. In this model there could be up to fifty lensed quasars in the sample, but most of them could only be detected by infrared spectroscopy.