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

October 2018 • 2018MNRAS.479.4345A

Authors • Agnello, A. • Lin, H. • Kuropatkin, N. • Buckley-Geer, E. • Anguita, T. • Schechter, P. L. • Morishita, T. • Motta, V. • Rojas, K. • Treu, T. • Amara, A. • Auger, M. 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-Lévy, A. • Bertin, E. • Bernstein, R. A. • Brooks, D. • Burke, D. L. • Rosell, A. Carnero • Carretero, J. • Cunha, C. E. • D'Andrea, C. B. • da Costa, L. N. • Desai, S. • Drlica-Wagner, A. • Eifler, T. F. • Flaugher, B. • García-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. A. • Sanchez, E. • Scarpine, V. • Schindler, R. • Schubnell, M. • Sevilla-Noarbe, I. • Smith, M. • Soares-Santos, M. • Sobreira, F. • Suchyta, E. • Swanson, M. E. C. • Tarle, G. • Tucker, D. • Wechsler, R.

Abstract • 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 z_l = 0.230 ± 0.002, respectively, has a deflector with radius R_eff ≈ 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 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.

Links

• PREPRINT http://arxiv.org/abs/1711.03971
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2018MNRAS.479.4345A
• ELECTR https://doi.org/10.1093%2Fmnras%2Fsty1419
• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2018MNRAS.479.4345A
• PDF http://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/sty1419
• DATA https://irsa.ipac.caltech.edu/bibdata/2018/A/2018MNRAS.479.4345A.html