COOL-LAMPS. IX. A Rare Duo of Quasars Each Lensed by a Single Massive Galaxy Cluster
Year: 2026
Type: article
Abstract: Wide-separation lensed quasars (WSLQs) are rare systems that arise from the chance alignment of two objects: a galaxy cluster and a background quasar. After two decades, only seven WSLQs have been found. Here, we report the discovery of COOL J1153+0755 by the COOL-LAMPS collaboration in DECaLS imaging and its confirmation with follow-up observations with the Magellan Telescopes and the Nordic Optical Telescope. This system features two multiply imaged quasars each lensed into four images by the same z = 0.4301 cluster: a classic broad-line Type I quasar at z = 1.524 (COOL J1153A) and a dust-obscured Type II quasar at z = 1.939 (COOL J1153B), with maximum image separations of 25 . ″ 6 and 26 . ″ 0 , respectively. We construct a lens model to estimate a projected cluster mass of M ( < 500 kpc) ∼ 3.3 × 10 14 M ⊙ and relative time delays between the three brightest images of each quasar of Δ t A3, A1 ∼ 800, Δ t A2, A1 ∼ 1200, Δ t B1, B3 ∼ 800, and Δ t B2, B3 ∼ 1000 days. COOL J1153A resides in a dense environment with three nearby galaxies, two of which are also strongly lensed. We identified COOL J1153+0755 without making a morphological cut in the DECaLS catalog; none of its multiple images are classified as point sources in those data, implying that morphology-based selection would miss such systems. COOL J1153+0755 expands the WSLQ sample from seven to eight systems (nine individual quasars), adding two powerful laboratories for probing black hole-galaxy coevolution at Cosmic Noon and for time-delay cosmography constraints on the Hubble constant, H 0 .
Source: The Astrophysical Journal
Authors: Erik Solhaug, Michael D. Gladders, Andi M. Kisare, Simon D. Mork, Kunwanhui Niu, Matthew B. Bayliss, Aidan P. Cloonan, Håkon Dahle, Isaiah R. Escapa, Michael K. Florian, Josh Garza, Gourav Khullar, Guillaume Mahler, Natalie Malagon, Kate Napier, Allison Noble, Jane R. Rigby, T. Emil Rivera-Thorsen, Riley Rosener, Keren Sharon, Antony A. Stark, Jamar Sullivan, Marie Tagliavia, Raul Teixeira, Kabelo Tsiane, Grace C. Wagner, Brian Welch, Yifan “Megan” Zhao
Institutions: University of Chicago, Arizona State University, University of Cincinnati, University of Oslo, Eureka Scientific, University of Washington, SLAC National Accelerator Laboratory, Stanford University, Stockholm University, University of Michigan, Center for Astrophysics Harvard & Smithsonian, International Space Science Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7161155915