{
  "id": "astro-ph/0511284",
  "version": "v1",
  "published": "2005-11-09T21:03:51.000Z",
  "updated": "2005-11-09T21:03:51.000Z",
  "title": "OVI in Elliptical Galaxies: Indicators of Cooling Flows",
  "authors": [
    "Joel N. Bregman",
    "Eric D. Miller",
    "Alex E. Athey",
    "Jimmy A. Irwin"
  ],
  "comment": "49 pages, 26 figures, ApJ, in press",
  "journal": "Astrophys.J.635:1031-1043,2005",
  "doi": "10.1086/497421",
  "categories": [
    "astro-ph"
  ],
  "abstract": "Early-type galaxies often contain a hot X-ray emitting interstellar medium (3-8E6 K) with an apparent radiative cooling time much less than a Hubble time. If unopposed by a heating mechanism, the gas will radiatively cool to temperatures <= 10E4 K at a rate proportional to L_X/T_X, typically 0.03-1 M_solar yr^-1. We can test if gas is cooling through the 3E5 K range by observing the OVI doublet, whose luminosity is proportional to the cooling rate. Here we report on a study of an unbiased sample of 24 galaxies, obtaining Far Ultraviolet Spectroscopic Explorer spectra to complement the X-ray data of ROSAT} and Chandra. The OVI line emission was detected in about 40% of the galaxies and at a luminosity level similar to the prediction from the cooling flow model. There is a correlation between Mdot_OVI and Mdot_X, although there is significant dispersion about the relationship, where the OVI is brighter or dimmer than expected by a factor of three or more. If the cooling flow picture is to be retained, this dispersion requires that cooling flows be time-dependent, as might occur by the activity of an AGN. However, of detected objects, those with the highest or lowest values of Mdot_OVI/Mdot_X are not systematically hot or cool, as one might predict from AGN heating.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2005-11-09T21:03:51.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cooling flow",
      "elliptical galaxies",
      "far ultraviolet spectroscopic explorer spectra",
      "obtaining far ultraviolet spectroscopic explorer",
      "indicators"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 49,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 697539
    }
  }
}