COOL–LAMPS. III. Discovery of a 25.″9 Separation Quasar Lensed by a Merging Galaxy Cluster*  

Martinez, Michael N.; Napier, Kate A.; Cloonan, Aidan P.; Sukay, Ezra; Gozman, Katya; Merz, Kaiya; Khullar, Gourav; Lin, Jason J.; Matthews Acuña, Owen S.; Medina, Elisabeth; Sanchez, Jorge A.; Sisco, Emily E.; Kavin Stein, Daniel J.; Tavangar, Kiyan; González, Juan Remolina; Mahler, Guillaume; Sharon, Keren; Dahle, Håkon; Gladders, Michael D.

Abstract

In the third paper from the COOL–LAMPS Collaboration, we report the discovery of COOL J0542-2125, a gravitationally lensed quasar at z = 1.84, observed as three images due to an intervening massive galaxy cluster at z = 0.61. The lensed quasar images were identified in a search for lens systems in recent public optical imaging data and have separations on the sky up to 25farcs9, wider than any previously known lensed quasar. The galaxy cluster acting as a strong lens appears to be in the process of merging, with two subclusters separated by ∼1 Mpc in the plane of the sky, and their central galaxies showing a radial velocity difference of ∼1000 km s−1. Both cluster cores show strongly lensed images of an assortment of background sources, as does the region between them. A preliminary strong lens model implies masses of ${M}_{\lt 250{\rm{k}}{\rm{p}}{\rm{c}}}={1.79}_{-0.01}^{+0.16}\times {10}^{14}\,{M}_{\odot }$ and ${M}_{\lt 250{\rm{k}}{\rm{p}}{\rm{c}}}={1.48}_{-0.10}^{+0.04}\times {10}^{14}\,{M}_{\odot }$ for the east and west subclusters, respectively. This line of sight is also coincident with an ROSAT ALL-sky Survey source, centered between the two confirmed cluster halos reminiscent of other major cluster-scale mergers. Archival and new follow-up imaging show flux variability in the quasar images of up to 0.4 mag within ∼1 yr, and new multicolor imaging data reveal a 2σ detection of the underlying quasar host. A lens system with this configuration offers rare opportunities for a range of future studies of both the lensed quasar and its host and the foreground cluster merger causing the lensing.

Citation

Martinez, M. N., Napier, K. A., Cloonan, A. P., Sukay, E., Gozman, K., Merz, K., …Gladders, M. D. (2023). COOL–LAMPS. III. Discovery of a 25.″9 Separation Quasar Lensed by a Merging Galaxy Cluster*  . Astrophysical Journal, 946(2), Article 63. https://doi.org/10.3847/1538-4357/acbe39

• Journal Article Type: Article
• Acceptance Date: Feb 21, 2023
• Online Publication Date: Mar 30, 2023
• Publication Date: Apr 1, 2023
• Deposit Date: Oct 31, 2023
• Publicly Available Date: Oct 31, 2023
• Journal: The Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 946
• Issue: 2
• Article Number: 63
• DOI: https://doi.org/10.3847/1538-4357/acbe39
• Keywords: Space and Planetary Science; Astronomy and Astrophysics
• Public URL: https://durham-repository.worktribe.com/output/1872433