{
  "abstract": "We present a detailed multiwavelength analysis of two gravitationally lensed z > 6 quasar candidates: J0109–5424 and P170+20. Using JWST/NIRSpec near-infrared (NIR) data from the Aether survey, we demonstrate that J0109–5424 is in fact a FeLoBAL quasar at z = 2.07, exhibiting strong iron broad absorption lines that mimic the Lyman break. From the Pa β emission line, we estimate a black hole mass of 3.9 × 10 ⁸ M ⊙ and a bolometric luminosity of L bol = 7.7 × 10 ⁴⁵ erg s ⁻¹ for this quasar. Follow-up HST/ACS Wide Field Channel imaging of P170+20 with the F555W filter, probing emission below the Lyman limit of the quasar, reveals a compact source located 0 . ″ 09 ± 0 . ″ 04 from the quasar position. Point spread function modeling and subtraction yield no evidence for extended emission. This is inconsistent with a foreground galaxy acting as a lens. Furthermore, we obtain Gemini South/Flamingos-2 and LBT/LUCI NIR observations to complement the existing optical Gemini North/GMOS spectrum of P170+20. Our spectral analysis shows that the observed spectral shape of P170+20 is consistent with a composite quasar and M dwarf spectrum. However, this interpretation remains uncertain, as a chance alignment between an ultracool dwarf and a quasar within 0 . ″ 1 would be unlikely. Overall, our findings establish J0109–5424 as an intermediate redshift source and do not favor the lensed nature of P170+20, although this possibility cannot be conclusively ruled out, highlighting the challenges of selecting lensed quasars at high redshift.",
  "abstract_shown": true,
  "affiliations": [
    "International Gemini Observatory/NSF NOIRLab",
    "INAF—Osservatorio di Astrofisica e Scienza dello Spazio di Bologna",
    "NSF NOIRLab",
    "University of California, Santa Cruz",
    "Max-Planck-Institut für Astronomie",
    "Institute for Fundamental Physics of the Universe",
    "INAF—Osservatorio Astronomico di Trieste",
    "University of Cambridge",
    "Center for Astrophysics ∣ Harvard & Smithsonian",
    "University of Hawai‘i",
    "University of Arizona",
    "Universidad Diego Portales",
    "University of Geneva",
    "University of Michigan"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 20,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Aurora Mata-Sanchez",
      "orcid": "0009-0006-0286-0639"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Emanuele Paolo Farina",
      "orcid": "0000-0002-6822-2254"
    },
    {
      "affs": [
        2
      ],
      "name": "Anniek J. Gloudemans",
      "orcid": "0009-0009-8274-441X"
    },
    {
      "affs": [
        3
      ],
      "name": "Debora Pelliccia",
      "orcid": "0000-0002-3007-0013"
    },
    {
      "affs": [
        1
      ],
      "name": "Roberto Decarli",
      "orcid": "0000-0002-2662-8803"
    },
    {
      "affs": [
        4
      ],
      "name": "Eduardo Bañados",
      "orcid": "0000-0002-2931-7824"
    },
    {
      "affs": [
        1,
        4
      ],
      "name": "Silvia Belladitta",
      "orcid": "0000-0003-4747-4484"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Manuela Bischetti",
      "orcid": "0000-0002-4314-021X"
    },
    {
      "affs": [
        4
      ],
      "name": "Sarah E. I. Bosman",
      "orcid": "0000-0001-8582-7012"
    },
    {
      "affs": [
        7
      ],
      "name": "Xander Byrne",
      "orcid": "0000-0001-9488-238X"
    },
    {
      "affs": [
        8
      ],
      "name": "Thomas Connor",
      "orcid": "0000-0002-7898-7664"
    },
    {
      "affs": [
        4
      ],
      "name": "Frederick Davies",
      "orcid": "0000-0003-0821-3644"
    },
    {
      "affs": [
        9
      ],
      "name": "Thales A. Gutcke",
      "orcid": "0000-0001-6179-7701"
    },
    {
      "affs": [
        10
      ],
      "name": "Weizhe Liu",
      "orcid": "0000-0003-3762-7344"
    },
    {
      "affs": [
        11
      ],
      "name": "Chiara Mazzucchelli",
      "orcid": "0000-0002-5941-5214"
    },
    {
      "affs": [
        12
      ],
      "name": "Romain Meyer",
      "orcid": "0000-0001-5492-4522"
    },
    {
      "affs": [
        0
      ],
      "name": "Silvia Onorato",
      "orcid": "0009-0009-1715-4157"
    },
    {
      "affs": [
        4
      ],
      "name": "Fabian Walter",
      "orcid": "0000-0003-4793-7880"
    },
    {
      "affs": [
        13
      ],
      "name": "Feige Wang",
      "orcid": "0000-0002-7633-431X"
    },
    {
      "affs": [
        13
      ],
      "name": "Jinyi Yang",
      "orcid": "0000-0001-5287-4242"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aqrfz94tpe07j.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4357/ae9d7e",
  "fulltext_url": null,
  "id": "aqrfz94tpe07j",
  "issns": [
    "0004-637X",
    "1538-4357"
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  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9d7e",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
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      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
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  "openalex": "W7215063494",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9d7e/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/aqrfz94tpe07j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:11Z",
      "native_id": "10.3847/1538-4357/ae9d7e",
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      "url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae9d7e"
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Galaxies: Formation, Evolution, Phenomena",
      "subfield": "galaxies"
    }
  ],
  "title": "To Be Lensed or Not to Be Lensed: On the Nature of the Alleged High- z Lensed Quasars J0109–5424 and P170+20",
  "title_text": "To Be Lensed or Not to Be Lensed: On the Nature of the Alleged High- z Lensed Quasars J0109–5424 and P170+20",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:11Z",
  "url": "https://research.draconitic.com/paper/aqrfz94tpe07j",
  "venue": "The Astrophysical Journal",
  "versions": []
}