Serendipitous discovery of quadruply imaged quasars: two diamonds

Lucey, John R.; Schechter, Paul L.; Smith, Russell J.; Anguita, T.

Abstract

Gravitationally lensed quasars are powerful and versatile astrophysical tools, but they are challengingly rare. In particular, only ∼25 well-characterized quadruple systems are known to date. To refine the target catalogue for the forthcoming Taipan Galaxy Survey, the images of a large number of sources are being visually inspected in order to identify objects that are confused by a foreground star or galaxies that have a distinct multicomponent structure. An unexpected by-product of this work has been the serendipitous discovery of about a dozen galaxies that appear to be lensing quasars, i.e. pairs or quartets of foreground stellar objects in close proximity to the target source. Here, we report two diamond-shaped systems. Follow-up spectroscopy with the IMACS instrument on the 6.5m Magellan Baade telescope confirms one of these as a z = 1.975 quasar quadruply lensed by a double galaxy at z = 0.293. Photometry from publicly available survey images supports the conclusion that the other system is a highly sheared quadruply imaged quasar. In starting with objects thought to be galaxies, our lens finding technique complements the conventional approach of first identifying sources with quasar-like colours and subsequently finding evidence of lensing.

Citation

Lucey, J. R., Schechter, P. L., Smith, R. J., & Anguita, T. (2018). Serendipitous discovery of quadruply imaged quasars: two diamonds. Monthly Notices of the Royal Astronomical Society, 476(1), 927-932. https://doi.org/10.1093/mnras/sty243

• Journal Article Type: Article
• Acceptance Date: Jan 12, 2018
• Online Publication Date: Feb 6, 2018
• Publication Date: May 1, 2018
• Deposit Date: Apr 3, 2018
• Publicly Available Date: Apr 3, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 476
• Issue: 1
• Pages: 927-932
• DOI: https://doi.org/10.1093/mnras/sty243
• Public URL: https://durham-repository.worktribe.com/output/1331338
• Related Public URLs: https://arxiv.org/abs/1711.02674