{
  "id": "2105.03735",
  "version": "v1",
  "published": "2021-05-08T16:37:40.000Z",
  "updated": "2021-05-08T16:37:40.000Z",
  "title": "[CII] $158\\,μ\\mathrm{m}$ line emission from Orion A. I. A template for extragalactic studies?",
  "authors": [
    "C. H. M. Pabst",
    "A. Hacar",
    "J. R. Goicoechea",
    "D. Teyssier",
    "O. Berné",
    "M. G. Wolfire",
    "R. D. Higgins",
    "E. T. Chambers",
    "S. Kabanovic",
    "R. Güsten",
    "J. Stutzki",
    "C. Kramer",
    "A. G. G. M. Tielens"
  ],
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "The [CII] $158\\,\\mu\\mathrm{m}$ fine-structure line is one of the dominant coolants of the neutral interstellar medium. It is hence one of the brightest far-infrared emission lines and can be observed not only in star-forming regions throughout the Galaxy, but also in the diffuse interstellar medium and in distant galaxies. [CII] line emission has been suggested to be a powerful tracer of star-formation. We aim to understand the origin of [CII] emission and its relation to other tracers of interstellar gas and dust. This includes a study of the heating efficiency of interstellar gas as traced by the [CII] line to test models of gas heating. We make use of a one-square-degree map of velocity-resolved [CII] line emission towards the Orion Nebula complex, including M43 and NGC 1977. The [CII] intensity is tightly correlated with PAH emission in the IRAC $8\\,\\mu\\mathrm{m}$ band and far-infrared emission from warm dust. The correlation between [CII] and CO(2-1) is affected by the detailed geometry of the region. We find particularly low [CII]-over-FIR intensity ratios towards large columns of (warm and cold) dust, which suggest the interpretation of the \"[CII] deficit\" in terms of a \"FIR excess\". A slight decrease in the FIR line-over-continuum intensity ratio can be attributed to a decreased heating efficiency of the gas. We find that, at the mapped spatial scales, predictions of the star-formation rate from [CII] emission underestimate the star-formation rate calculated from YSO counts in the Orion Nebula complex by an order of magnitude. [CII] emission from the Orion Nebula complex arises dominantly in the cloud surfaces, many viewed in edge-on geometry. [CII] emission from extended faint cloud surfaces may contribute significantly to the total [CII] emission on galactic scales.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-05-08T16:37:40.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "line emission",
      "extragalactic studies",
      "fir line-over-continuum intensity ratio",
      "cloud surfaces",
      "orion nebula complex arises"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}