{
  "id": "1405.0411",
  "version": "v2",
  "published": "2014-05-02T14:23:07.000Z",
  "updated": "2014-09-09T14:08:02.000Z",
  "title": "Atomic carbon as a powerful tracer of molecular gas in the high-redshift Universe: perspectives for ALMA",
  "authors": [
    "Matteo Tomassetti",
    "Cristiano Porciani",
    "Emilio Romano-Diaz",
    "Aaron D. Ludlow",
    "Padelis P. Papadopoulos"
  ],
  "comment": "5 pages, 4 figures, accepted for publication in MNRAS Letters",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We use a high-resolution hydrodynamic simulation that tracks the non-equilibrium abundance of molecular hydrogen within a massive high-redshift galaxy to produce mock Atacama Large Millimeter Array (ALMA) maps of the fine-structure lines of atomic carbon, CI 1-0 and CI 2-1. Inspired by recent observational and theoretical work, we assume that CI is thoroughly mixed within giant molecular clouds and demonstrate that its emission is an excellent proxy for H2. Nearly all of the H2 associated with the galaxy can be detected at redshifts z<4 using a compact interferometric configuration with a large synthesized beam (that does not resolve the target galaxy) in less than 4 h of integration time. Low-resolution imaging of the \\CI lines (in which the target galaxy is resolved into three to four beams) will detect ~80 per cent of the H2 in less than 12 h of aperture synthesis. In this case, the resulting data cube also provides the crucial information necessary for determining the dynamical state of the galaxy. We conclude that ALMA observations of the CI 1-0 and 2-1 emission are well-suited for extending the interval of cosmic look-back time over which the H2 distributions, the dynamical masses, and the Tully-Fisher relation of galaxies can be robustly probed.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-05-02T14:23:07.000Z",
      "title": "Atomic carbon as a tracer of molecular gas in high-redshift galaxies: perspectives for ALMA",
      "abstract": "We use a high-resolution simulation that tracks the non-equilibrium abundance of molecular hydrogen, H2, within a massive high-redshift galaxy to produce mock ALMA maps of the fine-structure lines of atomic carbon CI 1-0 and CI 2-1. Inspired by recent observational and theoretical work, we assume that CI is thoroughly mixed in giant molecular clouds and demonstrate that its emission is an excellent proxy for H2. The entire H2 mass of a galaxy at redshift z<4 can be detected using a compact interferometric configuration with a large synthesized beam (that does not resolve the target galaxy) in less than 1 hour of integration time. Low-resolution imaging of the CI lines (in which the target galaxy is resolved into 3-4 beams) will detect nearly 50-60 per cent of the molecular hydrogen in less than 12 hours. In this case, the data cube also provides valuable information regarding the dynamical state of the galaxy. We conclude that ALMA observations of the CI 1-0 and 2-1 emission will widely extend the interval of cosmic look-back time over which the H2 gas mass distribution, the dynamical masses, and the Tully-Fisher relation of galaxies can be accurately probed.",
      "comment": "5 pages, 4 figures, submitted to MNRAS Letters",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-09-09T14:08:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high-redshift galaxy",
      "molecular gas",
      "perspectives",
      "molecular hydrogen",
      "produce mock alma maps"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/mnrasl/slu137",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2014,
      "month": "Nov",
      "volume": 445,
      "number": 1
    },
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1293902,
      "adsabs": "2014MNRAS.445L.124T"
    }
  }
}