Gaia GraL: Gaia DR2 gravitational lens systems; I. New quadruply imaged quasar candidates around known quasars
<i>Context<i/>. 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 difficult to find. Even in this era of al...
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| Main Authors: | , , , |
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| Format: | Article (Journal) Editorial |
| Language: | English |
| Published: |
21 August 2018
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| In: |
Astronomy and astrophysics
Year: 2018, Volume: 616, Pages: L11 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201833337 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1051/0004-6361/201833337
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| Author Notes: | A. Krone-Martins, L. Delchambre, O. Wertz, C. Ducourant, F. Mignard, R. Teixeira, J. Klüter, J.-F. Le Campion, L. Galluccio, J. Surdej, U. Bastian, J. Wambsganss, M.J. Graham, S.G. Djorgovski, and E. Slezak |
| Summary: | <i>Context<i/>. 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 difficult to find. Even in this era of all-sky surveys, discovering them remains a great challenge, with barely a few hundred systems currently known.<i>Aims<i/>. We aim to discover new multiply imaged quasar candidates in the recently published <i>Gaia<i/> Data Release 2 (DR2), which is the astrometric and photometric all-sky survey with the highest spatial resolution that achieves effective resolutions from 0.4″ to 2.2″.<i>Methods<i/>. We cross-matched a merged list of quasars and candidates with <i>Gaia<i/> DR2 and found 1 839 143 counterparts within 0.5″. We then searched matches with more than two <i>Gaia<i/> DR2 counterparts within 6″. We further narrowed the resulting list using astrometry and photometry compatibility criteria between the <i>Gaia<i/> 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.<i>Results<i/>. We report the discovery of two quadruply imaged quasar candidates that are fully detected in <i>Gaia<i/> DR2. These are the most promising new quasar lens candidates from <i>Gaia<i/> DR2 and a simple singular isothermal ellipsoid lens model is able to reproduce their image positions to within ~1 mas. This Letter demonstrates the discovery potential of <i>Gaia<i/> for gravitational lenses. |
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| Item Description: | Gesehen am 27.02.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201833337 |