{
  "id": "1104.3235",
  "version": "v1",
  "published": "2011-04-16T12:28:45.000Z",
  "updated": "2011-04-16T12:28:45.000Z",
  "title": "Evidence for Rapidly Rotating Black Holes in FR I Radio Galaxies",
  "authors": [
    "Qingwen Wu",
    "Xinwu Cao",
    "Ding-Xiong Wang"
  ],
  "comment": "Accepted by ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We investigate the correlation between 151 MHz radio luminosity, L_151MHz, and jet power, P_jet, for a sample of low-power radio galaxies, of which the jet power is estimated from X-ray cavities. The jet power for a sample of FR I radio galaxies is estimated with the derived empirical correlation. We find that P_jet/L_Edd is positively correlated with Lx(2-10 keV)/L_Edd for FR Is, where L_Edd is the Eddington luminosity and Lx(2-10 keV) is 2-10 keV X-ray luminosity. We calculate the jet power of a hybrid model, as a variant of Blandford-Znajek model proposed by Meier, based on the global solution of the advection-dominated accretion flow (ADAF) surrounding a Kerr black hole (BH). Our model calculations suggest that the maximal jet power is a function of mass accretion rate and the black hole spin parameter j. The hard X-ray emission is believed to be mainly from the ADAFs in FR Is, and the mass accretion rate is therefore constrained with the X-ray emission in our ADAF model calculations. We find that the dimensionless angular momentum of BH j>~0.9 is required in order to reproduce the observed relation of P_jet/L_Edd-Lx(2-10 keV)/L_Edd for FR Is. Our conclusion will be strengthened if part of the X-ray emission is contributed by the jets. Our results suggest that BHs in FR I radio galaxies are rapidly spinning, which are almost not affected by the uncertainty of the black hole mass estimates.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-04-16T12:28:45.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "rapidly rotating black holes",
      "radio galaxies",
      "jet power",
      "x-ray emission",
      "mass accretion rate"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/735/1/50",
      "journal": "The Astrophysical Journal",
      "year": 2011,
      "month": "Jul",
      "volume": 735,
      "number": 1,
      "pages": 50
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 896505,
      "adsabs": "2011ApJ...735...50W"
    }
  }
}