{
  "abstract": "Flux ratio anomalies in multiply-imaged quasar lenses are a long-standing issue. Using a classical system B1422+231 as a case study, we investigate how typical non-clumpy perturbations beyond elliptical shapes -- multipoles $m_3, m_4$ and radial variations in $q, ϕ_q$ -- can account for the observed image positions and flux ratios under different observational precisions. We extract these perturbations from a pre-selected strong-lensing galaxy sample from the TNG100 simulation. Smooth macroscopic models (SIE+$γ$, EPL+$γ$) are then fitted to the observed image positions alone and to both positions and flux ratios, with and without including the extracted perturbations. With astrometric uncertainty of $σ_{p}=10$ mas, both macro-models alone can already successfully fit image positions within $3σ_{p}$. At $σ_{p}=2$ mas, however, 'astrometric anomalies' appear if smooth macro-models alone are adopted. In this case, adding the extracted perturbations can explain the anomalous image positions. When both positions and flux ratios are adopted, the SIE+$γ$ model family already shows 'flux ratio anomalies' at photometric uncertainty $σ_{f} \\le 10\\%$ (keeping $σ_{p}=10$ mas). When EPL+$γ$ is used, the smooth model alone can simultaneously fit both positions and flux ratios with $σ_{f}=10\\%, 5\\%$, but not with $σ_{f}=2\\%$, where 'flux ratio anomalies' appear. Adding all four types of extracted perturbations can rescue the macro-models and explain the observed anomalous flux ratios. We present important lessons learned regarding model flexibility and degeneracy.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.11559",
  "author_total": 6,
  "authors": [
    {
      "name": "Ruizhe Feng"
    },
    {
      "name": "Dandan Xu"
    },
    {
      "name": "Dominique Sluse"
    },
    {
      "name": "Giulia Despali"
    },
    {
      "name": "Anowar Shajib"
    },
    {
      "name": "Cai-Na Hao"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/86env1k24c4kh.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.11559",
  "fulltext_url": null,
  "id": "86env1k24c4kh",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.11559",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7168266265",
  "pdf_url": "https://arxiv.org/pdf/2607.11559",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/86env1k24c4kh.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:06Z",
      "native_id": "2607.11559",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.11559"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Can third- and fourth-order multipoles plus radial variation of iso-density ellipses explain the observed flux ratios in B1422$+$231? YES, and a lesson learned from a TNG100 lensing galaxy sample",
  "title_text": "Can third- and fourth-order multipoles plus radial variation of iso-density ellipses explain the observed flux ratios in B1422+231? YES, and a lesson learned from a TNG100 lensing galaxy sample",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:06Z",
  "url": "https://research.draconitic.com/paper/86env1k24c4kh",
  "venue": "arXiv",
  "versions": []
}