The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign - II. New quasar lenses from double component fitting

• Main Authors: Anguita, T, Schechter, PL, Kuropatkin, N, Morgan, ND, Ostrovski, F, Abramson, LE, Agnello, A, Apostolovski, Y, Fassnacht, CD, Hsueh, JW, Motta, V, Rojas, K, Rusu, CE, Treu, T, Williams, P, Auger, M, Buckley-Geer, E, Lin, H, McMahon, R, Abbott, TMC, Allam, S, Annis, J, Bernstein, RA, Bertin, E, Brooks, D, Burke, DL, Carnero Rosell, A, Carrasco-Kind, M, Carretero, J, Cunha, CE, D'Andrea, CB, De Vicente, J, DePoy, DL, Desai, S, Diehl, HT, Doel, P, Flaugher, B, Garcia-Bellido, J, Gerdes, DW, Gruen, D, Gruendl, RA, Gschwend, J, Hartley, WG, Hollowood, DL, Honscheid, K, James, J, Kuehn, K, Lima, M, Maia, MAG, Miquel, R, Plazas, AA, Sanchez, E, Scarpine, V, Smith, M, Soares-Santos, M, Sobreira, F, Suchyta, E, Tarle, G, Walker, AR
• Format: Article in Journal/Newspaper
• Language: English
• Published: OXFORD UNIV PRESS 2018
• Subjects: gravitational lensing: strong; techniques: image processing; surveys; quasars: general; sami
• Online Access: https://discovery.ucl.ac.uk/id/eprint/10063295/1/sty2172.pdf; https://discovery.ucl.ac.uk/id/eprint/10063295/

We report upon the follow-up of 34 candidate lensed quasars found in the Dark Energy Survey using NTT EFOSC, Magellan-IMACS, KECK-ESI, and SOAR-SAMI. These candidates were selected by a combination of double component fitting, morphological assessment, and colour analysis. Most systems followed up are indeed composed of at least one quasar image and 13 with two or more quasar images: two lenses, four projected binaries, and seven nearly identical quasar pairs (NIQs). The two systems confirmed as genuine gravitationally lensed quasars are one quadruple at zs = 1.713 and one double at zs = 1.515. Lens modelling of these two systems reveals that both systems require very little contribution from the environment to reproduce the image configuration. Nevertheless, small flux anomalies can be observed in one of the images of the quad. Further observations of nine inconclusive systems (including seven NIQs) will allow to confirm (or not) their gravitational lens nature.