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

A. Agnello, H. Lin, N. Kuropatkin, E. Buckley-Geer, T. Anguita, P. L. Schechter, T. Morishita, V. Motta, K. Rojas, T. Treu, A. Amara, M. W. Auger, F. Courbin, C. D. Fassnacht, J. Frieman, A. More, P. J. Marshall, R. G. McMahon, G. Meylan, S. H. SuyuK. Glazebrook, N. Morgan, B. Nord, T. M.C. Abbott, F. B. Abdalla, J. Annis, K. Bechtol, K. Benoit-Lévy, E. Bertin, R. A. Bernstein, D. Brooks, D. L. Burke, A. Carnero Rosell, J. Carretero, C. E. Cunha, C. B. D'Andrea, L. N. da Costa, S. Desai, A. Drlica-Wagner, T. F. Eifler, B. Flaugher, J. García-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, K. Honscheid, D. J. James, K. Kuehn, O. Lahav, M. Lima, M. A.G. Maia, M. March, F. Menanteau, R. Miquel, R. L.C. Ogando, A. A. Plazas, E. Sanchez, V. Scarpine, R. Schindler, M. Schubnell, I. Sevilla-Noarbe, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, G. Tarle, D. Tucker, R. Wechsler

Research output: Contribution to journalArticlepeer-review


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 ≈2.0 arcsec and ≈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 zl = 0.230 ± 0.002, respectively, has a deflector with radius Reff ≈ 3.4 arcsec, stellar mass log(M*/M) = 11.64+0.20 -0.43, and extended isophotal shape variation. Simple lens models yield Einstein radii RE = (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 zs = 1.390 ± 0.001 and zl = 0.335 ± 0.002, and Einstein radius RE = (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.

Original languageEnglish (US)
Pages (from-to)4345-4354
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Oct 1 2018


  • Gravitational lensing: strong
  • Methods: statistical
  • Surveys
  • Techniques: image processing

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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