{
  "abstract": "We present an untargeted survey of 21 cm H i absorption systems based on the second data release of the FAST All Sky H I survey (FASHI DR2), covering approximately 19,500 deg ² at z ≲ 0.09. A total of 132 H i absorbers are identified, including approximately 60 new discoveries, forming one of the largest homogeneous samples of low-redshift H i absorbers assembled to date. The sample extends to continuum flux densities as low as 2.6 mJy, substantially below the limits of previous flux-limited surveys. The absorber population is dominated by narrow systems ( W ₅₀ < 100 km s ⁻¹ ), while broad absorbers ( W ₅₀ > 200 km s ⁻¹ ) account for 13.6% of the sample. Most absorbers are optically thin, with a median optical depth of τ HI ≈ 0.14. The velocity-offset distribution is broadly symmetric about the systemic velocities of the host galaxies. The associated absorbers are preferentially found in massive, actively star-forming galaxies. We find tentative evidence for a weak anticorrelation between H i column density and stellar mass, although the relation exhibits substantial scatter. These results provide the first statistical characterization of the low-redshift H i absorber population based on the FASHI DR2 sample and establish a valuable benchmark for future H i absorption surveys with next-generation radio facilities.",
  "abstract_shown": true,
  "affiliations": [
    "Chinese Academy of Sciences",
    "Guizhou University",
    "Shanghai Jiao Tong University",
    "Chinese Academy of Sciences South America Center for Astronomy"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Chuan-Peng Zhang",
      "orcid": "0000-0002-4428-3183"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Ming Zhu",
      "orcid": "0000-0001-6083-956X"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Peng Jiang",
      "orcid": "0000-0002-5387-7952"
    },
    {
      "affs": [
        0
      ],
      "name": "Hong Guo",
      "orcid": "0000-0003-4936-8247"
    },
    {
      "affs": [
        2
      ],
      "name": "Yizhou Gu"
    },
    {
      "affs": [
        3
      ],
      "name": "Cheng Cheng",
      "orcid": "0000-0003-0202-0534"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Jin-Long Xu",
      "orcid": "0000-0002-7384-797X"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Nai-Ping Yu"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Xiao-Lan Liu",
      "orcid": "0000-0002-1768-9591"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Bo Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ennnk40gbmsz6.bib",
  "cited_by": 0,
  "doi": "10.3847/1538-4365/aea991",
  "fulltext_url": null,
  "id": "ennnk40gbmsz6",
  "issns": [
    "0067-0049",
    "1538-4365"
  ],
  "landing_url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea991",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
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  "openalex": "W7204167310",
  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea991/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/ennnk40gbmsz6.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:15Z",
      "native_id": "10.3847/1538-4365/aea991",
      "source": "crossref",
      "url": "https://iopscience.iop.org/article/10.3847/1538-4365/aea991"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Galaxies: Formation, Evolution, Phenomena",
      "subfield": "galaxies"
    }
  ],
  "title": "FASHI DR2: A Catalog of 132 Low-redshift H I 21 cm Absorption Systems",
  "title_text": "FASHI DR2: A Catalog of 132 Low-redshift H I 21 cm Absorption Systems",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:15Z",
  "url": "https://research.draconitic.com/paper/ennnk40gbmsz6",
  "venue": "The Astrophysical Journal Supplement Series",
  "versions": [
    {
      "doi": "10.48550/arxiv.2608.23385",
      "pid": "d44nq77txxhhk",
      "relation": "preprint",
      "title": "FASHI DR2: A Catalog of 132 Low-Redshift HI 21 cm Absorption Systems",
      "venue": "arXiv"
    }
  ]
}