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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Gaia GraL: Gaia DR2 gravitational lens systems I. New quadruply imaged quasar candidates around known quasars

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Krone-Martins, A. [1] ; Delchambre, L. [2] ; Wertz, O. [3] ; Ducourant, C. [4] ; Mignard, F. [5] ; Teixeira, R. [6] ; Klueter, J. [7] ; Le Campion, J. -F. [4] ; Galluccio, L. [5] ; Surdej, J. [2] ; Bastian, U. [7] ; Wambsganss, J. [7] ; Graham, M. J. [8] ; Djorgovski, S. G. [8] ; Slezak, E. [5]
Total Authors: 15
[1] Univ Lisbon, Fac Ciencias, CENTRA, Ed C8, P-1749016 Lisbon - Portugal
[2] Univ Liege, Inst Astrophys & Geophys, 19c, Allee 6 Aout, B-4000 Liege - Belgium
[3] Univ Bonn, Argelander Inst Astron, Hugel 71, D-53121 Bonn - Germany
[4] Univ Bordeaux, CNRS, Lab Astrophys Bordeaux, B18N, Allee Geoffroy St Hilaire, F-33615 Pessac - France
[5] Univ Cote dAzur, Observ Cote dAzur, CNRS, Lab Lagrange, Blvd Observ, CS 34229, F-06304 Nice - France
[6] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao, 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil
[7] Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, Monchhofstr 12-14, D-69120 Heidelberg - Germany
[8] CALTECH, 1200 E Calif Blvd, Pasadena, CA 91125 - USA
Total Affiliations: 8
Document type: Journal article
Source: Astronomy & Astrophysics; v. 616, AUG 21 2018.
Web of Science Citations: 9

Context. Multiply imaged gravitationally lensed quasars are among the most interesting and useful observable extragalactic phenomena. Because their study constitutes a unique tool in various fields of astronomy, they are highly sought, but di ffi cult to find. Even in this era of all-sky surveys, discovering them remains a great challenge, with barely a few hundred systems currently known. Aims. We aim to discover new multiply imaged quasar candidates in the recently published Gaia Data Release 2 (DR2), which is the astrometric and photometric all-sky survey with the highest spatial resolution that achieves e ff ective resolutions from 0.4{''} to 2.2{''}. Methods. We cross-matched a merged list of quasars and candidates with Gaia DR2 and found 1 839 143 counterparts within 0.5 00. We then searched matches with more than two Gaia DR2 counterparts within 6 00. We further narrowed the resulting list using astrometry and photometry compatibility criteria between the Gaia DR2 counterparts. A supervised machine-learning method, called extremely randomized trees, was finally adopted to assign a probability of being lensed to each remaining system. Results. We report the discovery of two quadruply imaged quasar candidates that are fully detected in Gaia DR2. These are the most promising new quasar lens candidates from Gaia DR2 and a simple singular isothermal ellipsoid lens model is able to reproduce their image positions to within similar to 1 mas. This Letter demonstrates the discovery potential of Gaia for gravitational lenses. (AU)

FAPESP's process: 09/54006-4 - A computer cluster for the Astronomy Department of the University of São Paulo Institute of Astronomy, Geophysics and Atmospheric Sciences and for the Cruzeiro do Sul University Astrophysics Center
Grantee:Elisabete Maria de Gouveia Dal Pino
Support type: Multi-user Equipment Program