Bright lenses are easy to find: Spectroscopic confirmation of lensed quasars in the Southern Sky

C. Spiniello, A. Agnello, A. V. Sergeyev, T. Anguita, O. Rodriguez, N. R. Napolitano, C. Tortora

Published 2018-11-02Version 1

Gravitationally lensed quasars are valuable, but extremely rare, probes of observational cosmology and extragalactic astrophysics. Progress in these fields has been limited just by the paucity of systems with good ancillary data. Here we present a first spectroscopic confirmation of lenses discovered from optical ground based surveys in the Southern Hemisphere. We have targeted 7 high-graded candidates, selected with new techniques, with NTT-EFOSC2, and confirmed 5 of them. We provide source spectroscopic redshifts, image separations, $gri$ photometry and first lens model parameters. The success rate of $\sim 70\%$ confirms our forecasts, based on the comparison between the number of candidate doubles and quadruplets in our searches over a $\approx5000\text{ deg}^2$ footprint and theoretical predictions.