DES meets Gaia: discovery of strongly lensed quasars from a multiplet search

Agnello, A.; Lin, H.; Kuropatkin, N.; Buckley-Geer, E.; Anguita, T.; Schechter, L.; Morishita, T.; Motta, V.; Rojas, K.; Treu, T.; Amara, A.; Auger, W.; Courbin, F.; Fassnacht, C. D.; Frieman, J.; More, A.; Marshall, P. J.; McMahon, R. G.; Meylan, G.; Suyu, S. H.; Glazebrook, K.; Morgan, N.; Nord, B.; Abbott, T. M. C.; Abdalla, F. B.; Annis, J.; Bechtol, K.; Benoit-Levy, A.; Bertin, E.; Bernstein, R. A.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Drlica-Wagner, A.; Eifler, T. F.; Flaugher, B.; Garcia-Bellido, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Menanteau, F.; Miquel, R.; Ogando, R. L. C.; Plazas, A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, E. C.; Tarle, G.; Tucker, D.; Wechsler, R.
2018
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
DOI
10.1093/mnras/sty1419
We report the discovery, spectroscopic confirmation, and first lens models of the first, strongly lensed quasars from a combined search in WISE and Gaia-DR1 over the DES footprint. Their Einstein radii span a range between approximate to 2.0 arcsec and approximate to 0.4 arcsec. Two of these (WGD2038-4008, RA = 20: 38: 02.65, Dec. = -40: 08: 14.64; WGD2021-4115, RA = 20: 21: 39.45, Dec. = -41:15:57.11) also have confirmed deflector redshifts. The four-image lens WGD2038-4008, with source and deflector redshifts s = 0.777 +/- 0.001 and z(l) = 0.230 +/- 0.002, respectively, has a deflector with radius R-eff approximate to 3.4 arcsec, stellar mass log(M-star /M-circle dot) = 11.64(-0.43)(+ 0.20), and extended isophotal shape variation. Simple lens models yield Einstein radii R-E = (1.30 +/- 0.04) arcsec, axis ratio q = 0.75 +/- 0.1 (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lens WGD2021-4115 has z(s) = 1.390 +/- 0.001 and z(l) = 0.335 +/- 0.002, and Einstein radius R-E = (1.1 +/- 0.1) arcsec, but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. Analogous lens model degeneracies hold for the other six lenses (J0146-1133, J0150-4041, J0235-2433, J0245-0556, J0259-2338, and J0508-2748) shown in this paper.