{
  "id": "1403.5265",
  "version": "v1",
  "published": "2014-03-20T20:00:32.000Z",
  "updated": "2014-03-20T20:00:32.000Z",
  "title": "Temporal Self-Organization in Galaxy Formation",
  "authors": [
    "Renyue Cen"
  ],
  "comment": "10 pages, 4 figures, ApJ Letters in press, comments always welcome",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We report on the discovery of a relation between the number of star formation (SF) peaks per unit time, $\\nu_{\\rm peak}$, and the size of the temporal smoothing window function, $\\Delta t$, used to define the peaks: $\\nu_{\\rm peak}\\propto\\Delta t^{1-\\phi}$ ($\\phi\\sim 1.618$). This relation holds over the range of $\\Delta t=10$ to $1000$Myr that can be reliably computed, using a large sample of galaxies obtained from a state-of-the-art cosmological hydrodynamic simulation. This means that the temporal distribution of SF peaks in galaxies as a population is fractal with a Hausdorff fractal dimension equal to $\\phi-1$. This finding reveals, for the first time, that the superficially chaotic process of galaxy formation is underlined by a temporal self-organization up to at least one gigayear. It is tempting to suggest that, given the known existence of spatial fractals (such as the power-law two-point function of galaxies), there is a joint spatio-temporal self-organization in galaxy formation. From an observational perspective, it will be urgent to devise diagnostics to probe SF histories of galaxies with good temporal resolution to facilitate a test of this prediction. If confirmed, it would provide unambiguous evidence for a new picture of galaxy formation that is interaction driven, cooperative and coherent in and between time and space. Unravelling its origin may hold the key to understanding galaxy formation.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-03-20T20:00:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galaxy formation",
      "hausdorff fractal dimension equal",
      "state-of-the-art cosmological hydrodynamic simulation",
      "probe sf histories",
      "joint spatio-temporal self-organization"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/2041-8205/785/2/L21",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "Apr",
      "volume": 785,
      "number": 2
    },
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1286809,
      "adsabs": "2014ApJ...785L..21C"
    }
  }
}