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

    Monthly notices of the Royal Astronomical Society, 05/2023, Volume: 522, Issue: 4
    Journal Article

    ABSTRACT We report the discovery of a triply imaged active galactic nucleus (AGN), lensed by the galaxy cluster MACS J0035.4−2015 (zd = 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 zspec = 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 $M_{\star }\simeq 10^{9.2}\, \mathrm{M}_{\odot }$ . 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.