{
  "abstract": "We study geometrically thin equatorial disc images in the static, axisymmetric q-metric spacetime using backward ray tracing. The Schwarzschild solution is recovered at $q=0$; for the nonzero deformations considered here, $r=2M$ is a curvature singularity rather than an event horizon. For a distant nearly face-on observer, we construct the first three equatorial transfer functions $r_m(b;q)$. In the {Schwarzschild} limit, the resolved third-crossing interval contains the critical impact parameter $b=3\\sqrt{3}M$. As $q$ increases from $-0.3$ to $0.3$, the branch center shifts from $b_{3,c}/M\\simeq3.716$ to $6.702$. In units of the physical monopole mass $\\mathcal M=(1+q)M$, it instead decreases from $b_{3,c}/\\mathcal M\\simeq5.309$ to $5.156$. Much of the displacement in metric-parameter units therefore reflects the changing monopole scale. At fixed $\\mathcal M$, the inclined first-intersection maps show that the contour dimensions increase with $q$, with larger relative changes near the inner disc. A prescribed power-law emissivity and relativistic frequency-shift weighting yield direct images whose integrated flux differs from the Schwarzschild value by at most $2.4\\%$. Between the endpoint models, the horizontal median-flux position increases by $8.8\\%$ and the interquartile width by $14.5\\%$. Within this emission prescription, the residual deformation dependence appears mainly as a displacement and broadening of the brightness distribution. Higher-order radiative contributions are not included.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.07259",
  "author_total": 6,
  "authors": [
    {
      "name": "Saken Toktarbay"
    },
    {
      "name": "Manas Khassanov"
    },
    {
      "name": "Aray Muratkhan"
    },
    {
      "name": "Zhantay Muratkhan"
    },
    {
      "name": "Aliya Taukenova"
    },
    {
      "name": "Hernando Quevedo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4216jrtkhgs6j.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.07259",
  "fulltext_url": null,
  "id": "4216jrtkhgs6j",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.07259",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "openalex",
      "3103|Astrophysical Phenomena and Observations"
    ]
  ],
  "openalex": "W7212006067",
  "pdf_url": "https://arxiv.org/pdf/2609.07259",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4216jrtkhgs6j.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2609.07259",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.07259"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Thin accretion-disc transfer functions in the q-metric spacetime: quadrupolar lensing signatures",
  "title_text": "Thin accretion-disc transfer functions in the q-metric spacetime: quadrupolar lensing signatures",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/4216jrtkhgs6j",
  "venue": "arXiv",
  "versions": []
}