{
  "id": "1412.2749",
  "version": "v1",
  "published": "2014-12-08T21:00:01.000Z",
  "updated": "2014-12-08T21:00:01.000Z",
  "title": "The SILCC (SImulating the LifeCycle of molecular Clouds) project: I. Chemical evolution of the supernova-driven ISM",
  "authors": [
    "S. K. Walch",
    "P. Girichidis",
    "T. Naab",
    "A. Gatto",
    "S. C. O. Glover",
    "R. Wünsch",
    "R. S Klessen",
    "P. C. Clark",
    "T. Peters",
    "C. Baczynski"
  ],
  "comment": "30 pages, 23 figures, submitted to MNRAS. Comments welcome! For movies of the simulations and download of selected Flash data see the SILCC website: http://www.astro.uni-koeln.de/silcc",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "The SILCC project (SImulating the Life-Cycle of molecular Clouds) aims at a more self-consistent understanding of the interstellar medium (ISM) on small scales and its link to galaxy evolution. We simulate the evolution of the multi-phase ISM in a 500 pc x 500 pc x 10 kpc region of a galactic disc, with a gas surface density of $\\Sigma_{_{\\rm GAS}} = 10 \\;{\\rm M}_\\odot/{\\rm pc}^2$. The Flash 4.1 simulations include an external potential, self-gravity, magnetic fields, heating and radiative cooling, time-dependent chemistry of H$_2$ and CO considering (self-) shielding, and supernova (SN) feedback. We explore SN explosions at different (fixed) rates in high-density regions (peak), in random locations (random), in a combination of both (mixed), or clustered in space and time (clustered). Only random or clustered models with self-gravity (which evolve similarly) are in agreement with observations. Molecular hydrogen forms in dense filaments and clumps and contributes 20% - 40% to the total mass, whereas most of the mass (55% - 75%) is in atomic hydrogen. The ionised gas contributes <10%. For high SN rates (0.5 dex above Kennicutt-Schmidt) as well as for peak and mixed driving the formation of H$_2$ is strongly suppressed. Also without self-gravity the H$_2$ fraction is significantly lower ($\\sim$ 5%). Most of the volume is filled with hot gas ($\\sim$90% within $\\pm$2 kpc). Only for random or clustered driving, a vertically expanding warm component of atomic hydrogen indicates a fountain flow. Magnetic fields have little impact on the final disc structure. However, they affect dense gas ($n\\gtrsim 10\\;{\\rm cm}^{-3}$) and delay H$_2$ formation. We highlight that individual chemical species, in particular atomic hydrogen, populate different ISM phases and cannot be accurately accounted for by simple temperature-/density-based phase cut-offs.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-12-08T21:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "molecular clouds",
      "supernova-driven ism",
      "chemical evolution",
      "atomic hydrogen",
      "magnetic fields"
    ],
    "publication": {
      "doi": "10.1093/mnras/stv1975",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2015,
      "month": "Nov",
      "volume": 454,
      "number": 1,
      "pages": 238
    },
    "note": {
      "typesetting": "TeX",
      "pages": 30,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015MNRAS.454..238W"
    }
  }
}