TY - JOUR
T1 - SLICE
T2 - SPT-CL J0546-5345—A Prominent Strong-lensing Cluster at z = 1.07
AU - Allingham, Joseph F.V.
AU - Zitrin, Adi
AU - Golubchik, Miriam
AU - Furtak, Lukas J.
AU - Bayliss, Matthew
AU - Cerny, Catherine
AU - Diego, Jose M.
AU - Edge, Alastair C.
AU - Gassis, Raven
AU - Gladders, Michael D.
AU - Jauzac, Mathilde
AU - Lagattuta, David J.
AU - Leroy, Gavin
AU - Limousin, Marceau
AU - Mahler, Guillaume
AU - Meena, Ashish K.
AU - Natarajan, Priyamvada
AU - Sharon, Keren
N1 - Publisher Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
PY - 2025/9/1
Y1 - 2025/9/1
N2 - Massive galaxy clusters act as prominent strong lenses. Due to a combination of observational biases, cluster evolution, and lensing efficiency, most of the known cluster lenses lie typically at zl ∼ 0.2-0.7, with only a few prominent examples at higher redshifts. Here we report the first strong-lensing analysis of the massive galaxy cluster SPT-CL J0546-5345 at a redshift zl = 1.07. This cluster was first detected through the Sunyaev-Zel’dovich effect, with a high estimated mass for its redshift of M200,c = (7.95 ± 0.92) × 1014 M⊙. Using recent JWST/NIRCam and archival Hubble Space Telescope imaging, we identify at least 10 secure and 6 candidate sets of multiply imaged background galaxies, which we use to constrain the mass distribution in the cluster. We derive effective Einstein radii of θE = 18 . ″ 1 ± 1 . ″ 8 for a source at zs = 3 and θE = 27 . ″ 9 ± 2 . ″ 8 for a source at zs = 9. The total projected mass within a 200 kpc radius around the strong-lensing region is M (<200 kpc) = (1.9 ± 0.3) × 1014 M⊙. While our results rely on photometric redshifts warranting spectroscopic follow-up, this central mass resembles that of the Hubble Frontier Fields clusters—although SPT-CL J0546-5345 is observed when the Universe was ∼3-4 Gyr younger. Amongst the multiply imaged sources, we identify a hyperbolic-umbilic-like configuration, and, thanks to its point-like morphology, a possible active galactic nucleus (AGN). If confirmed spectroscopically, it will add to just a handful of other quasars and AGN known to be multiply lensed by galaxy clusters.
AB - Massive galaxy clusters act as prominent strong lenses. Due to a combination of observational biases, cluster evolution, and lensing efficiency, most of the known cluster lenses lie typically at zl ∼ 0.2-0.7, with only a few prominent examples at higher redshifts. Here we report the first strong-lensing analysis of the massive galaxy cluster SPT-CL J0546-5345 at a redshift zl = 1.07. This cluster was first detected through the Sunyaev-Zel’dovich effect, with a high estimated mass for its redshift of M200,c = (7.95 ± 0.92) × 1014 M⊙. Using recent JWST/NIRCam and archival Hubble Space Telescope imaging, we identify at least 10 secure and 6 candidate sets of multiply imaged background galaxies, which we use to constrain the mass distribution in the cluster. We derive effective Einstein radii of θE = 18 . ″ 1 ± 1 . ″ 8 for a source at zs = 3 and θE = 27 . ″ 9 ± 2 . ″ 8 for a source at zs = 9. The total projected mass within a 200 kpc radius around the strong-lensing region is M (<200 kpc) = (1.9 ± 0.3) × 1014 M⊙. While our results rely on photometric redshifts warranting spectroscopic follow-up, this central mass resembles that of the Hubble Frontier Fields clusters—although SPT-CL J0546-5345 is observed when the Universe was ∼3-4 Gyr younger. Amongst the multiply imaged sources, we identify a hyperbolic-umbilic-like configuration, and, thanks to its point-like morphology, a possible active galactic nucleus (AGN). If confirmed spectroscopically, it will add to just a handful of other quasars and AGN known to be multiply lensed by galaxy clusters.
UR - https://www.scopus.com/pages/publications/105014970998
U2 - 10.3847/2041-8213/adfa85
DO - 10.3847/2041-8213/adfa85
M3 - Article
AN - SCOPUS:105014970998
SN - 2041-8205
VL - 990
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L25
ER -