Quasar lenses and pairs in the VST-ATLAS and Gaia

Agnello, A.; Schechter, P.L.; Morgan, N.D.; Treu, T.; Grillo, C.; Malesani, D.; Anguita, T.; Apostolovski, Y.; Rusu, C.E.; Motta, V.; Rojas, K.; Chehade, B.; Shanks, T.

Abstract

We report on discovery results from a quasar lens search in the ATLAS-DR3 public footprint. Spectroscopic follow-up campaigns, conducted at the 2.6 m Nordic Optical Telescope (La Palma) and 3.6 m New Technology Telescope (La Silla) in 2016, yielded seven pairs of quasars exhibiting the same lines at the same redshift and monotonic flux ratios with wavelength (hereafter NIQs, nearly identical quasar pairs). Magellan spectra of A0140−1152 (01h40m03 s. 0–11d52m19 s. 0, zs = 1.807) confirm it as a lens with deflector at zl = 0.277 and Einstein radius θE = (0.73 ± 0.02) arcsec. Follow-up imaging of the NIQ A2213−2652 (22h13m38 s. 4–26d52m27 s. 1) reveals the deflector galaxy and confirms it as a lens. We show the use of spatial resolution from the Gaia mission to select lenses and list additional systems from a WISE-Gaia-ATLAS search, yielding three additional lenses (02h35m27 s. 4–24d33m13 s. 2, 02h59m33s–23d38m01 s. 8, 01h46m32 s. 9–11d33m39 s. 0). The overall sample consists of 11 lenses/NIQs, plus three lenses known before 2016, over the ATLAS-DR3 footprint (≈3500 deg2). Finally, we discuss future prospects for objective classification of pair/NIQ/contaminant spectra.

Citation

Agnello, A., Schechter, P., Morgan, N., Treu, T., Grillo, C., Malesani, D., …Shanks, T. (2018). Quasar lenses and pairs in the VST-ATLAS and Gaia. Monthly Notices of the Royal Astronomical Society, 475(2), 2086-2096. https://doi.org/10.1093/mnras/stx3226

• Journal Article Type: Article
• Acceptance Date: Dec 8, 2017
• Online Publication Date: Dec 13, 2017
• Publication Date: Apr 1, 2018
• Deposit Date: Mar 29, 2018
• Publicly Available Date: Mar 29, 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: 475
• Issue: 2
• Pages: 2086-2096
• DOI: https://doi.org/10.1093/mnras/stx3226
• Public URL: https://durham-repository.worktribe.com/output/1363276