HerS-3: An Exceptional Einstein Cross Reveals a Massive Dark Matter Halo
Journal article, 2025
We present a study of HerS-3, a dusty star-forming galaxy at zspec = 3.0607, which is gravitationally amplified into an Einstein cross with a fifth image of the background galaxy seen at the center of the cross. Detailed 1 mm spectroscopy and imaging with NOEMA and the Atacama Large Millimeter/submillimeter Array resolve the individual images and show that each of the five images display a series of molecular lines that have similar central velocities, unambiguously confirming that they have identical redshifts. The Hubble Space Telescope F110W image reveals a foreground lensing group of four galaxies with a photometric redshift zphot ∼ 1.0. Lens models that only include the four visible galaxies are unable to reproduce the properties of HerS-3. By adding a fifth massive component, lying southeast of the brightest galaxy of the group, the source reconstruction is able to match the peak emission, shape, and orientation for each of the five images. The fact that no galaxy is detected near that position indicates the presence of a massive dark matter halo in the lensing galaxy group. In the source plane, HerS-3 appears as an infrared luminous starburst galaxy seen nearly edge on. The serendipitous discovery of this exceptional Einstein cross offers a potential laboratory for exploring at small spatial scales a nuclear starburst at the peak of cosmic evolution and studying the properties of a massive dark matter halo associated with the lensing galaxy group.
Author
P. Cox
Institut d 'Astrophysique de Paris
Kirsty May Butler
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
C. R. Keeton
Rutgers University
L. Eid
Rutgers University
E. Borsato
University of Padua
Tom Bakx
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
R. Neri
Institut de Radioastronomie Millimétrique (IRAM)
B. M. Jones
University of Cologne
Prachi Prajapati
University of Cologne
Max Planck Society
A. J. Baker
University of the Western Cape
Rutgers University
S. Berta
Institut de Radioastronomie Millimétrique (IRAM)
A. Cooray
University of California
E. M. Corsini
University of Padua
Istituto nazionale di astrofisica (INAF)
L. Marchetti
Istituto di Radioastronomia
University of Cape Town
A.A. Omont
Institut d 'Astrophysique de Paris
A. Beelen
Laboratoire d'Astrophysique de Marseille
R. Gavazzi
Laboratoire d'Astrophysique de Marseille
D. Ismail
Observatoire Astronomique de Strasbourg
R. J. Ivison
University of Edinburgh
Dublin Institute for Advanced Studies
M. Krips
Institut de Radioastronomie Millimétrique (IRAM)
M. Lehnert
Université de Lyon
Institut d 'Astrophysique de Paris
H. Messias
Atacama Large Millimeter-submillimeter Array (ALMA)
European Southern Observatory Santiago
D. A. Riechers
University of Cologne
C. Vlahakis
National Radio Astronomy Observatory
A. Weiß
Max Planck Society
P. van der Werf
Leiden University
Chentao Yang
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 991 1 53The Origin and Fate of Dust in Our Universe
Knut and Alice Wallenberg Foundation (KAW 2019.0443), 2020-06-01 -- 2023-05-31.
Knut and Alice Wallenberg Foundation (KAW 2020.0081), 2021-07-01 -- 2026-06-30.
Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.3847/1538-4357/adf204