{
  "id": "astro-ph/9704076",
  "version": "v1",
  "published": "1997-04-09T22:37:13.000Z",
  "updated": "1997-04-09T22:37:13.000Z",
  "title": "The Delayed Formation of Dwarf Galaxies",
  "authors": [
    "Jeremy Kepner",
    "Arif Babul",
    "David Spergel"
  ],
  "comment": "23 pages (including 8 figures). Figures 3 and 8 best viewed in color",
  "journal": "ApJ 487 (1997) 61",
  "doi": "10.1086/304602",
  "categories": [
    "astro-ph"
  ],
  "abstract": "One of the largest uncertainties in understanding the effect of a background UV field on galaxy formation is the intensity and evolution of the radiation field with redshift. This work attempts to shed light on this issue by computing the quasi-hydrostatic equilibrium states of gas in spherically symmetric dark matter halos (roughly corresponding to dwarf galaxies) as a function of the amplitude of the background UV field. We integrate the full equations of radiative transfer, heating, cooling and non-equilibrium chemistry for nine species: H, H^+, H^-,H_2, H_2^+, He, He^+, He^{++}, and e^-. As the amplitude of the UV background is decreased the gas in the core of the dwarf goes through three stages characterized by the predominance of ionized (H^+), neutral (H) and molecular (H_2) hydrogen. Characterizing the gas state of a dwarf galaxy with the radiation field allows us to estimate its behavior for a variety of models of the background UV flux. Our results indicate that a typical radiation field can easily delay the collapse of gas in halos corresponding to 1-$\\sigma$ CDM perturbations with circular velocities less than 30 km/s.",
  "revisions": [
    {
      "version": "v1",
      "updated": "1997-04-09T22:37:13.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "dwarf galaxy",
      "delayed formation",
      "background uv field",
      "radiation field",
      "spherically symmetric dark matter halos"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 23,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 461098
    }
  }
}