{
  "abstract": "Observations of the 21-cm signal can probe energy injection into the intergalactic medium arising from dark matter annihilation during cosmic dawn and reionization. For s-wave annihilation, the annihilation rate depends on the squared dark matter density, making the 21-cm signal sensitive to dark matter halo substructure. In this work, we extend the numerical method of DM21cm to address spatially inhomogeneous s-wave annihilation including subhalo effects, using semi-analytical treatment of SASHIMI-C. Our numerical results show that the projected HERA limit for the $γγ$ annihilation channel is stronger than the Leo~T bound within the dark matter mass range of $m_χ\\leq 3\\,{\\rm keV}$, whereas the projected HERA limit for the $e^+e^-$ annihilation channel is the strongest among the existing bounds for $m_χ\\sim 0.1$--$1\\,{\\rm GeV}$.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.21479",
  "author_total": 2,
  "authors": [
    {
      "name": "Zixuan Xu"
    },
    {
      "name": "Sibo Zheng"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/a85qm6jqdc7w4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.21479",
  "fulltext_url": null,
  "id": "a85qm6jqdc7w4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.21479",
  "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.CO"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3106|Dark Matter and Cosmic Phenomena"
    ]
  ],
  "openalex": "W7213899607",
  "pdf_url": "https://arxiv.org/pdf/2609.21479",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/a85qm6jqdc7w4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:03Z",
      "native_id": "2609.21479",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.21479"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "21-cm Constraints on S-wave Dark Matter Annihilation with Subhalo-enhanced Effects",
  "title_text": "21-cm Constraints on S-wave Dark Matter Annihilation with Subhalo-enhanced Effects",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:03Z",
  "url": "https://research.draconitic.com/paper/a85qm6jqdc7w4",
  "venue": "arXiv",
  "versions": []
}