{
  "id": "astro-ph/0409353",
  "version": "v1",
  "published": "2004-09-14T20:40:28.000Z",
  "updated": "2004-09-14T20:40:28.000Z",
  "title": "Coarse-graining the distribution function of cold dark matter II",
  "authors": [
    "R. N. Henriksen"
  ],
  "comment": "MNRAS, in press",
  "doi": "10.1111/j.1365-2966.2004.08397.x",
  "categories": [
    "astro-ph"
  ],
  "abstract": "We study analytically the coarse and fine-grained distribution function established by the self-similar infall of collisionless matter. We find this function explicitly for isotropic and spherically symmetric systems in terms of cosmological initial conditions. The coarse-grained function is structureless and steady but the familiar phase space sheet sub-structure is recovered in the fine-grained limit. By breaking the self-similarity of the halo infall we are able to argue for a central density flattening. In addition there will be an edge steepening. The best fitting analytic density function is likely to be provided by a high order polytrope fit smoothly to an outer power law of index -3 for isolated systems. There may be a transition to a -4 power law in the outer regions of tidally truncated systems. We find a progressive central flattening that is expected to end either in the non-singular isothermal sphere, or in non-singular metastable polytropic cores. Therefore a collisionless system may pass through a family of polytropes of increasing order, finally approaching the limit of the non-singular isothermal sphere, if the `violent' collective relaxation is frequently re-excited by `merger' events. Our results suggest that no physics beyond that of the moderate collective relaxation often known as `violent relaxation' (due we think to wave-particle scattering) is necessary to explain the nature of dark matter density profiles.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2004-09-14T20:40:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cold dark matter",
      "distribution function",
      "fitting analytic density function",
      "order polytrope fit",
      "non-singular isothermal sphere"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "Wiley-Blackwell",
      "journal": "J. Finance"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 659363
    }
  }
}