Discovery of two gravitationally lensed quasars in the Dark Energy Survey
Agnello, A.; Treu, T.; Ostrovski, F.; Schechter, P. L.; Buckley-Geer, E. J.; Lin, H.; Auger, M. W.; Courbin, F.; Fassnacht, C. D.; Frieman, J.; Kuropatkin, N.; Marshall, P. J.; Mcmahon, R. G.; Meylan, G.; More, A.; Suyu, S. H.; Rusu, C. E.; Finley, D.; Abbott, T.; Abdalla, F. B.; Allam, S.; Annis, J.; Banerji, M.; Benoit-Levy, A.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Kind, M. Carrasco; Carretero, J.; Cunha, C. E.; D'Andrea, C. B.; Da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Gerdes, D. W.; Gruen, D.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Tucker, D.; Walker, A. R.; Wechsler, R. H.; Zhang, Y.
2015

Abstract

We present spectroscopic confirmation of two new gravitationally lensed quasars, discovered in the Dark Energy Survey (DES) and Wide-field Infrared Survey Explorer (WISE) based on their multiband photometry and extended morphology in DES images. Images of DES J0115-5244 show a red galaxy with two blue point sources at either side, which are images of the same quasar at z(s) = 1.64 as obtained by our long-slit spectroscopic data. The Einstein radius estimated from the DES images is 0.51 arcsec. DES J2146-0047 is in the area of overlap between DES and the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fibre spectrum shows a quasar component at z(s) = 2.38 and absorption by Mg Pi and Fe Pi at z(1) = 0.799, which we tentatively associate with the foreground lens galaxy. Our long-slit spectra show that the blue components are resolved images of the same quasar. The Einstein radius is 0.68 arcsec, corresponding to an enclosed mass of 1.6 x 10(11) M-circle dot. Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data mining and model-based selection that is being applied to the entire DES data set.

Details

Title Discovery of two gravitationally lensed quasars in the Dark Energy Survey
Author(s) Agnello, A. ; Treu, T. ; Ostrovski, F. ; Schechter, P. L. ; Buckley-Geer, E. J. ; Lin, H. ; Auger, M. W. ; Courbin, F. ; Fassnacht, C. D. ; Frieman, J. ; Kuropatkin, N. ; Marshall, P. J. ; Mcmahon, R. G. ; Meylan, G. ; More, A. ; Suyu, S. H. ; Rusu, C. E. ; Finley, D. ; Abbott, T. ; Abdalla, F. B. ; Allam, S. ; Annis, J. ; Banerji, M. ; Benoit-Levy, A. ; Bertin, E. ; Brooks, D. ; Burke, D. L. ; Carnero Rosell, A. ; Kind, M. Carrasco ; Carretero, J. ; Cunha, C. E. ; D'Andrea, C. B. ; Da Costa, L. N. ; Desai, S. ; Diehl, H. T. ; Dietrich, J. P. ; Doel, P. ; Eifler, T. F. ; Estrada, J. ; Fausti Neto, A. ; Flaugher, B. ; Fosalba, P. ; Gerdes, D. W. ; Gruen, D. ; Gutierrez, G. ; Honscheid, K. ; James, D. J. ; Kuehn, K. ; Lahav, O. ; Lima, M. ; Maia, M. A. G. ; March, M. ; Marshall, J. L. ; Martini, P. ; Melchior, P. ; Miller, C. J. ; Miquel, R. ; Nichol, R. C. ; Ogando, R. ; Plazas, A. A. ; Reil, K. ; Romer, A. K. ; Roodman, A. ; Sako, M. ; Sanchez, E. ; Santiago, B. ; Scarpine, V. ; Schubnell, M. ; Sevilla-Noarbe, I. ; Smith, R. C. ; Soares-Santos, M. ; Sobreira, F. ; Suchyta, E. ; Swanson, M. E. C. ; Tarle, G. ; Thaler, J. ; Tucker, D. ; Walker, A. R. ; Wechsler, R. H. ; Zhang, Y.
Published in Monthly Notices Of The Royal Astronomical Society
Pagination 6
Volume 454
Issue 2
Pages 1260-1265
Date 2015
Publisher Oxford, Oxford Univ Press
ISSN 0035-8711
Keywords
DOI https://doi.org/10.1093/mnras/stv2171
Other identifier(s) View record in Web of Science
Laboratories LASTRO
Record Appears in Scientific production and competences > SB - School of Basic Sciences > IPHYS - Institute of Physics > LASTRO - Laboratory of Astrophysics
Peer-reviewed publications
Work produced at EPFL
Journal Articles
Published
Record creation date 2016-02-16