{
  "abstract": "Several repeating fast radio burst (FRB) sources exhibit host-frame dispersion measure (DM) excesses far exceeding those expected from the interstellar medium in their host galaxies, implying a substantial contribution from the sub-kiloparsec-scale local environment. These excesses are often attributed to an expanding supernova remnant; however, this canonical interpretation does not explain their apparent preference for low-metallicity dwarf galaxy hosts, suggesting that the mechanism producing the local DM is coupled to the properties of the host galaxy. In this work, we investigate whether the H II regions generated by young, massive stellar associations can simultaneously explain these DM excesses and their preferential association with low-metallicity dwarf galaxies. We develop a semi-analytic model for FRB-emitting neutron stars in cluster-forming molecular clouds and perform idealized one-dimensional radiation-hydrodynamic simulations using time-dependent ionizing luminosities from pySTARBURST99. Our findings indicate that high-mass $(M_\\star \\sim 10^5-10^6\\;M_\\odot)$, young ($\\lesssim 10\\;{\\rm Myr}$) stellar associations in low-metallicity environments (LMC-like or lower) can produce ${\\rm DM}_{\\rm HII} \\gtrsim 10^3\\;{\\rm pc\\;cm^{-3}}$ for FRBs that form early ($\\lesssim 5$ Myr) and remain embedded in the ionized gas. The low-mass/metallicity preference arises from dust: absorption of the Lyman continuum suppresses the ionized column at higher metallicity, making extreme local DMs preferentially generated in dust-poor, low-metallicity environments. At cosmological distances, selection of a metal-rich, massive, and quiescent host galaxy sample where such extreme local contributions are likely to be suppressed may yield a cleaner FRB sample for using extragalactic DMs as tracers of the intervening intergalactic and circumgalactic media.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.27779",
  "author_total": 3,
  "authors": [
    {
      "name": "Eliza C. Diggins"
    },
    {
      "name": "Calvin Leung"
    },
    {
      "name": "Wenbin Lu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bj89gm6z5be4q.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.27779",
  "fulltext_url": null,
  "id": "bj89gm6z5be4q",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.27779",
  "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.GA"
    ],
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ],
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7204853992",
  "pdf_url": "https://arxiv.org/pdf/2608.27779",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bj89gm6z5be4q.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:22Z",
      "native_id": "2608.27779",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.27779"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "High Dispersion Measure Fast Radio Bursts from Young, Dust-Poor H II Regions",
  "title_text": "High Dispersion Measure Fast Radio Bursts from Young, Dust-Poor H II Regions",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:22Z",
  "url": "https://research.draconitic.com/paper/bj89gm6z5be4q",
  "venue": "arXiv",
  "versions": []
}