Three quasi-stellar objects acting as strong gravitational lenses⋆
F. Courbin1, C. Faure1, S. G. Djorgovski2,3, F. Rérat1, M. Tewes1, G. Meylan1, D. Stern4, A. Mahabal2, T. Boroson5, R. Dheeraj6 and D. Sluse7,8
1 Laboratoire d’astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
2 Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
3 Distinguished Visiting Professor, King Abdulaziz University, 21589 Jeddah, Saudi Arabia
4 Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 169-221, Pasadena, CA 91109, USA
5 National Optical Astronomy Observatory, Tucson, AZ 85719, USA
6 The University of Maryland, College Park, MD 20742, USA
7 Astronomisches Rechen-Institut am Zentrum für Astronomie der Universität Heidelberg, Mönchhofstrasse 12-14, 69120 Heidelberg, Germany
8 Argelander-Institut für Astronomie, Bonn Universität, Auf dem Hügel 71, 53121 Bonn, Germany
Received: 5 September 2011
Accepted: 21 October 2011
We report the discovery of three new cases of quasi-stellar objects (QSOs) acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (zQSO = 0.293, zs = 0.412), SDSS J0919+2720 (zQSO = 0.209, zs = 0.558), SDSS J1005+4016 (zQSO = 0.230, zs = 0.441). The selection was carried out using a sample of 22,298 SDSS spectra displaying at least four emission lines at a redshift beyond that of the foreground QSO. The lensing nature is confirmed from Keck imaging and spectroscopy, as well as from HST/WFC3 imaging in the F475W and F814W filters. Two of the QSOs have face-on spiral host galaxies and the third is a QSO+galaxy pair. The velocity dispersion of the host galaxies, inferred from simple lens modeling, is between σ = 210 and 285 km s-1, making these host galaxies comparable in mass with the SLACS sample of early-type strong lenses.
Key words: gravitational lensing: strong / quasars: individual: SDSS J0013+1523 / quasars: individual: SDSS J0827+5224 / quasars: individual: SDSS J0919+2720 / quasars: individual: SDSS J1005+4016
Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Also based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #GO12233.
© ESO, 2012