{
  "abstract": "We present an untargeted survey of 21 cm HI absorption systems based on the second data release of the FAST All Sky HI survey (FASHI DR2), covering approximately 19,500 deg$^{2}$ at $z\\lesssim0.09$. A total of 132 HI absorbers are identified, including approximately 60 new discoveries, forming one of the largest homogeneous samples of low-redshift HI 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 $τ_{\\rm HI}\\approx0.14$. 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 anti-correlation between HI column density and stellar mass, although the relation exhibits substantial scatter. These results provide the first statistical characterization of the low-redshift HI absorber population based on the FASHI DR2 sample and establish a valuable benchmark for future HI absorption surveys with next-generation radio facilities.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.23385",
  "author_total": 10,
  "authors": [
    {
      "name": "Chuan-Peng Zhang"
    },
    {
      "name": "Ming Zhu"
    },
    {
      "name": "Peng Jiang"
    },
    {
      "name": "Hong Guo"
    },
    {
      "name": "Yizhou Gu"
    },
    {
      "name": "Cheng Cheng"
    },
    {
      "name": "Jin-Long Xu"
    },
    {
      "name": "Nai-Ping Yu"
    },
    {
      "name": "Xiao-Lan Liu"
    },
    {
      "name": "Bo Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d44nq77txxhhk.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.23385",
  "fulltext_url": null,
  "id": "d44nq77txxhhk",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.23385",
  "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/2608.23385",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-26",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/d44nq77txxhhk.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2608.23385",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.23385"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "FASHI DR2: A Catalog of 132 Low-Redshift HI 21 cm Absorption Systems",
  "title_text": "FASHI DR2: A Catalog of 132 Low-Redshift HI 21 cm Absorption Systems",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:50Z",
  "url": "https://research.draconitic.com/paper/d44nq77txxhhk",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4365/aea991",
      "pid": "ennnk40gbmsz6",
      "relation": "published-as",
      "title": "FASHI DR2: A Catalog of 132 Low-redshift H I 21 cm Absorption Systems",
      "venue": "The Astrophysical Journal Supplement Series"
    }
  ]
}