{
  "abstract": "The [C II] 158 µm line is widely used to trace star formation and the gas contents of high-redshift galaxies. However, it remains unclear under which physical conditions it reliably traces the molecular reservoir, and whether a unique conversion factor α [C II] can be applied across cosmic time. We investigated the evolution of the relation between the [C II] luminosity and dense neutral gas mass from z ≃ 10 to z ≃ 0.2 using the VINTERGATAN simulation, a high-resolution cosmological zoom-in of a Milky Way-like galaxy. We post-processed the snapshots with the SKIRT radiative transfer code to generate synthetic [C II] data cubes. We measured global and spatially resolved (100 pc) relations between [C II] luminosity (L [C II] ), star formation rate (SFR), and dense neutral gas mass (M DN ). We followed the redshift evolution of the [C II]-to-dense neutral gas conversion factor α [C II] , and linked these trends to the evolution of the interstellar medium (ISM) phases. The global L [C II] -M DN and L [C II] -SFR relations evolve from a steep, [C II]-deficient regime at a very low metallicity to an almost linear behaviour, similar to calibrations at z ≈ 2, once the ISM reaches Z gas ≳ 0.05-0.1 Z ⊙ at z ≲ 5. Over this evolution, α [C II] spans nearly three orders of magnitude, from ≳10 4 down to ≈10 M ⊙ L -1 ⊙ , even though the [C II] emission remains spatially correlated with the dense neutral gas. We provide prescriptions for α [C II] based on integrated and local quantities. The latter recovers the dense neutral mass of VINTERGATAN within factors of the of order unity, whereas global relations depending only on L [C II] and/or the integrated metallicity fail by up to an order of magnitude during major and minor merger epochs. A unique, redshift-independent α [C II] therefore cannot recover dense neutral gas masses across the regimes we explored. [C II] remains a viable tracer of dense neutral gas at very high redshifts, but only when used with conversion factors that explicitly account for metallicity, ISM phase mix, and merger events.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "C. Accard"
    },
    {
      "name": "F. Renaud"
    },
    {
      "name": "K. Kraljic"
    },
    {
      "name": "D. Ismail"
    },
    {
      "name": "M. Béthermin"
    },
    {
      "name": "O. Agertz"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bht8wg0pja1yg.bib",
  "cited_by": 0,
  "doi": "10.1051/0004-6361/202660531",
  "fulltext_url": null,
  "id": "bht8wg0pja1yg",
  "issns": [
    "0004-6361",
    "1432-0746"
  ],
  "landing_url": "https://hal.science/hal-05853353v1",
  "language": "en",
  "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": [
    [
      "hal",
      "0.sdu"
    ],
    [
      "hal",
      "1.sdu.astr"
    ],
    [
      "hal",
      "2.sdu.astr.ga"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7155174497",
  "pdf_url": "https://hal.science/hal-05853353/document",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-24",
  "publisher": "EDP Sciences",
  "ris": "https://research.draconitic.com/paper/bht8wg0pja1yg.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T12:20:13Z",
      "native_id": "hal-05853353",
      "source": "hal",
      "url": "https://hal.science/hal-05853353v1"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "hal:2.sdu.astr.ga",
      "subfield": "galaxies"
    },
    {
      "field": "earth",
      "origin": "hal:0.sdu",
      "subfield": "general"
    }
  ],
  "title": "Cosmic evolution of the [C II]-to-dense neutral gas relation",
  "title_text": "Cosmic evolution of the [C II]-to-dense neutral gas relation",
  "type": "peer-reviewed",
  "updated_at": "2026-11-07T12:20:25Z",
  "url": "https://research.draconitic.com/paper/bht8wg0pja1yg",
  "venue": "Astronomy & Astrophysics - A&A",
  "versions": []
}