{
  "abstract": "Circumgalactic Medium (CGM) plays a critical role in galactic evolution, serving as the primary reservoir for accretion and outflows. In this work, we present a novel statistical analysis to derive CGM metallicity from the dispersion measure (DM) of 25 Fast Radio Burst (FRB) sightlines. By combining metallicity-dependent oxygen absorption DM estimates with metallicity-independent FRB DMs, we directly constrain the metallicity of the hot phase of the Milky Way (MW) CGM. Considering different diffuse baryon fractions ($f_{\\text{d}} = 0.0, 0.6, 0.8$) in the Intergalactic Medium (IGM) and intervening halos, the median metallicities of CGM are $Z_{\\text{CGM}} = 0.12_{-0.04}^{+0.09} \\, Z_{\\odot}$, $0.26_{-0.12}^{+0.18} \\, Z_{\\odot}$, and $0.39_{-0.20}^{+0.26} \\, Z_{\\odot}$, respectively, by the bootstrapping method. Super-solar metallicity is seen in multiple sightlines for $f_d=0.8$, which is implausible for MW CGM metallicities. Even under conservative lower-bound estimates ($f_{\\text{d}} = 0.0$), the inferred CGM metallicity significantly exceeds expectations for IGM accretion ($Z_{\\text{IGM}} \\lesssim 0.1 \\, Z_{\\odot}$), providing strong empirical evidence that a large fraction of the metal-enriched galactic feedback material is efficiently retained within the Milky Way CGM. Furthermore, we observe significant sightline-to-sightline variation in inferred metallicities, pointing toward a highly anisotropic multi-phase CGM shaped by complex interactions between feedback outflows and cosmic accretion.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.40609",
  "author_total": 5,
  "authors": [
    {
      "name": "Manami Roy"
    },
    {
      "name": "Sanskriti Das"
    },
    {
      "name": "Smita Mathur"
    },
    {
      "name": "Anjali Gupta"
    },
    {
      "name": "Yair Krongold"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/esx4xah048et0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.40609",
  "fulltext_url": null,
  "id": "esx4xah048et0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.40609",
  "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.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.40609",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-29",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/esx4xah048et0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:28Z",
      "native_id": "2610.40609",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.40609"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "From Dispersion to Metallicity: Probing the Milky Way Circumgalactic Medium with Fast Radio Bursts",
  "title_text": "From Dispersion to Metallicity: Probing the Milky Way Circumgalactic Medium with Fast Radio Bursts",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:47Z",
  "url": "https://research.draconitic.com/paper/esx4xah048et0",
  "venue": "arXiv",
  "versions": []
}