{
  "abstract": "We investigate rotating black holes surrounded by perfect-fluid dark matter (PFDM), described by the parameter \\(k\\), and determine the Kerr-connected region of the \\((a/M,k/M)\\) parameter space that contains an event horizon. The critical value \\(k_{\\mathrm c}(a)\\), obtained from the degenerate-horizon conditions \\(Δ(r_{\\mathrm c})=Δ'(r_{\\mathrm c})=0\\), defines the boundary between black-hole and horizonless configurations. We derive an exact parametric form of this extremal boundary and show that its near-Kerr behavior includes a logarithmic correction; therefore, \\(k_{\\mathrm c}/M\\simeq2.8828(1-a/M)^{1.5377}\\) is only an empirical fit over \\(0.90\\leq a/M\\leq0.999\\), not an asymptotic scaling law. For horizon-bearing solutions, we calculate unstable spherical photon orbits and the shadow's mean radius, area, and distortion, finding that increasing \\(k/M\\) shifts the photon region inward and reduces the shadow size. Backward ray tracing through a phenomenological optically thin disk, tested on independent \\(41^2\\), \\(81^2\\), and \\(161^2\\) image grids, confirms this trend: for \\(a/M=0.9\\) and an inclination of \\(17^\\circ\\), the \\(20~μ\\mathrm{as}\\) beam-convolved ridge diameter decreases from \\(42.47\\) to \\(37.88~μ\\mathrm{as}\\) as \\(k/M\\) increases from 0 to \\(0.08\\), with the two finest grids agreeing to within \\(0.5\\%\\). Thus, PFDM produces a consistent contraction from the horizon and photon region to the geometric shadow and image ridge, although these illustrative images do not provide an Event Horizon Telescope constraint because they lack a self-consistent emission model and interferometric likelihood analysis.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Journal of High Energy Astrophysics 56 (2027) 100766",
  "arxiv": "2611.08520",
  "author_total": 1,
  "authors": [
    {
      "name": "G. G. L. Nashed"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/abca1nqm3g5m3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.08520",
  "fulltext_url": null,
  "id": "abca1nqm3g5m3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.08520",
  "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",
      "physics.gen-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.08520",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/abca1nqm3g5m3.ris",
  "sources": [
    {
      "first_seen": "2026-11-10T06:21:04Z",
      "native_id": "2611.08520",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.08520"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.gen-ph",
      "subfield": "general"
    }
  ],
  "title": "Rotating Black Holes in Perfect Fluid Dark Matter: Horizons, Photon Orbits, and Shadows",
  "title_text": "Rotating Black Holes in Perfect Fluid Dark Matter: Horizons, Photon Orbits, and Shadows",
  "type": "preprint",
  "updated_at": "2026-11-10T06:21:04Z",
  "url": "https://research.draconitic.com/paper/abca1nqm3g5m3",
  "venue": "arXiv",
  "versions": []
}