{
  "abstract": "Galactic observations have shown that N2H+ intensities preferentially trace star-forming dense molecular gas compared with HCN or HCO+, which are conventionally used as dense-gas tracers in extragalactic studies. In this study, we aim to verify this trend in the nearby star-forming galaxy M83. Using ALMA, we observed the J=1-0 transitions of N2H+ and HCN, along with the 1-mm and 3-mm continuum, and analyzed the archival CO(1-0) data. The data achieved a spatial resolution of 48 pc in the southwestern bar-end region of M83, covering an area of 2.1 kpc x 1.8 kpc. N2H+ and HCN intensities are approximately linearly correlated, indicating that HCN luminosity can still reasonably predict the amount of dense gas as well as N2H+ luminosity does. However, in regions with high column densities, N2H+ becomes a super-linear function of HCN, suggesting that the N2H+ emission is more sensitive to dense gas than HCN. We employed a radiative transfer model that predicts line intensities as a function of column density, adopting parametric column density probability distribution functions (N-PDFs) to describe the underlying column density distribution. The model demonstrates that the observed linear or superlinear trend can be explained by a log-normal distribution only or a log-normal and a power-law tail distribution in the N-PDF. Furthermore, the N2H+ intensity is significantly more sensitive to the power-law tail than the HCN intensity. In addition, our analysis incorporating archival data shows that N2H+ is a less reliable tracer of dense gas in galactic center regions, where warmer temperatures may promote N2H+ destruction.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.21142",
  "author_total": 9,
  "authors": [
    {
      "name": "Nanase Harada"
    },
    {
      "name": "Yuri Nishimura"
    },
    {
      "name": "Toshiki Saito"
    },
    {
      "name": "Mario Tafalla"
    },
    {
      "name": "Jin Koda"
    },
    {
      "name": "Doris Arzoumanian"
    },
    {
      "name": "Sophia K. Stuber"
    },
    {
      "name": "Akihiko Hirota"
    },
    {
      "name": "Yoshimasa Watanabe"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4zdg27ewn4vfy.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.21142",
  "fulltext_url": null,
  "id": "4zdg27ewn4vfy",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.21142",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.21142",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4zdg27ewn4vfy.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.21142",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.21142"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "ALMA observations towards M83 reveal N2H+ tracing dense gas",
  "title_text": "ALMA observations towards M83 reveal N2H+ tracing dense gas",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/4zdg27ewn4vfy",
  "venue": "arXiv",
  "versions": []
}