{
  "id": "astro-ph/0002364",
  "version": "v1",
  "published": "2000-02-18T02:12:12.000Z",
  "updated": "2000-02-18T02:12:12.000Z",
  "title": "Nonlinear Velocity-Density Coupling: Analysis by Second-Order Perturbation Theory",
  "authors": [
    "Naoki Seto"
  ],
  "comment": "16 pages including 2 figures, ApJ 537 in press (July 1)",
  "journal": "Astrophys.J. 537 (2000) 21",
  "doi": "10.1086/309012",
  "categories": [
    "astro-ph"
  ],
  "abstract": "Cosmological linear perturbation theory predicts that the peculiar velocity $V(x)$ and the matter overdensity $\\delta(x)$ at a same point $x$ are statistically independent quantities, as log as the initial density fluctuations are random Gaussian distributed. However nonlinear gravitational effects might change the situation. Using framework of second-order perturbation theory and the Edgeworth expansion method, we study local density dependence of bulk velocity dispersion that is coarse-grained at a weakly nonlinear scale. For a typical CDM model, the first nonlinear correction of this constrained bulk velocity dispersion amounts to $\\sim 0.3\\delta$ (Gaussian smoothing) at a weakly nonlinear scale with a very weak dependence on cosmological parameters. We also compare our analytical prediction with published numerical results given at nonlinear regimes.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2000-02-18T02:12:12.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "second-order perturbation theory",
      "nonlinear velocity-density coupling",
      "weakly nonlinear scale",
      "constrained bulk velocity dispersion amounts",
      "cosmological linear perturbation theory predicts"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 544696
    }
  }
}