{
  "abstract": "Repeating fast radio bursts may reside in young supernova remnant (SNR) environments whose evolving plasma contributes to the observed dispersion measure (DM). We use two-dimensional axisymmetric hydrodynamic simulations to study the interaction between a continuous anisotropic wind from a young neutron star and homologously expanding supernova ejecta. We follow the evolution to approximately 160 yr and calculate the source-local DM along different viewing directions, using a passive tracer to separate wind and nonwind contributions. In the fiducial model, the strongly polar-focused wind inflates a low-density cavity, while the swept-up shell remains broadly rounded and the DM shows moderate angular variation. The DM is dominated by ejecta and swept-up nonwind material. The solid-angle-averaged ambient-subtracted excess DM declines throughout the evolution, approximately following $t_{\\rm age}^{-2}$ during the first several tens of years and becoming modestly steeper later. Variations in wind and ejecta parameters modify the normalization, early evolution, and viewing-angle dependence, but the angle-averaged DM declines in all models, while different bipolar wind profiles produce similar long-term evolution. For FRB 20190520B, the fiducial model reaches a decline rate comparable to the source-frame value inferred from observations at approximately 20 yr, when the mean excess DM is approximately $1.8\\times10^2~{\\rm pc,cm^{-3}}$. Thus, such a young environment can retain a substantial electron column while producing a rapid secular decrease. Repeater diversity suggests that SNR-driven expansion may coexist with additional time-dependent plasma structures or ionization changes.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: The Astrophysical Journal, 1009, 223 (2026)",
  "arxiv": "2608.01342",
  "author_total": 5,
  "authors": [
    {
      "name": "Xiang-Er Fang"
    },
    {
      "name": "Zhen-Yin Zhao"
    },
    {
      "name": "Yi-Qing Lin"
    },
    {
      "name": "Hao-Tian Lan"
    },
    {
      "name": "Fa-Yin Wang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0vscsw1022ej7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.01342",
  "fulltext_url": null,
  "id": "0vscsw1022ej7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.01342",
  "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",
      "astro-ph.HE"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2608.01342",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/0vscsw1022ej7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:48Z",
      "native_id": "2608.01342",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.01342"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure",
  "title_text": "Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:48Z",
  "url": "https://research.draconitic.com/paper/0vscsw1022ej7",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4357/aea3f0",
      "pid": "bfshdd55w6jyx",
      "relation": "published-as",
      "title": "Propagation Diagnostics of Supernova Remnant Environments around Young Repeating Fast Radio Bursts. I. Hydrodynamic Evolution of the Source-local Dispersion Measure",
      "venue": "The Astrophysical Journal"
    }
  ]
}