A variable active galactic nucleus at z = 2.06 triply-imaged by the galaxy cluster MACS J0035.4−2015

Lukas J. Furtak, Ramesh Mainali, Adi Zitrin, Adèle Plat, Seiji Fujimoto, Megan Donahue, Erica J. Nelson, Franz E. Bauer, Ryosuke Uematsu, Gabriel B. Caminha, Felipe Andrade-Santos, Larry D. Bradley, Karina I. Caputi, Stéphane Charlot, Jacopo Chevallard, Dan Coe, Emma Curtis-Lake, Daniel Espada, Brenda L. Frye, Kirsten K. KnudsenAnton M. Koekemoer, Kotaro Kohno, Vasily Kokorev, Nicolas Laporte, Minju M. Lee, Brian C. Lemaux, Georgios E. Magdis, Keren Sharon, Daniel P. Stark, Yuanyuan Su, Katherine A. Suess, Yoshihiro Ueda, Hideki Umehata, Alba Vidal-García, John F. Wu

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


We report the discovery of a triply imaged active galactic nucleus (AGN), lensed by the galaxy cluster MACS J0035.4−2015 (z d = 0.352). The object is detected in Hubble Space Telescope imaging taken for the RELICS program. It appears to have a quasi-stellar nucleus consistent with a point-source, with a de-magnified radius of re ≲ 100 pc. The object is spectroscopically confirmed to be an AGN at z spec = 2.063 ± 0.005 showing broad rest-frame UV emission lines, and detected in both X-ray observations with Chandra and in ALCS ALMA band 6 (1.2 mm) imaging. It has a relatively faint rest-frame UV luminosity for a quasar-like object, MUV, 1450 = −19.7 ± 0.2. The object adds to just a few quasars or other X-ray sources known to be multiply lensed by a galaxy cluster. Some diffuse emission from the host galaxy is faintly seen around the nucleus, and there is a faint object nearby sharing the same multiple-imaging symmetry and geometric redshift, possibly an interacting galaxy or a star-forming knot in the host. We present an accompanying lens model, calculate the magnifications and time delays, and infer the physical properties of the source. We find the rest-frame UV continuum and emission lines to be dominated by the AGN, and the optical emission to be dominated by the host galaxy of modest stellar mass M✶ ≃ 109.2 M⊙. We also observe some variation in the AGN emission with time, which may suggest that the AGN used to be more active. This object adds a low-redshift counterpart to several relatively faint AGN recently uncovered at high redshifts with HST and JWST.

Original languageEnglish
Pages (from-to)5142-5151
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Jul 1 2023

Bibliographical note

Publisher Copyright:
© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.


  • cosmology: observations
  • galaxies: Seyfert
  • galaxies: clusters: individual: MACS J0035.4-2015
  • galaxies: nuclei
  • gravitational lensing: strong
  • quasars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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