{
  "id": "0902.3704",
  "version": "v2",
  "published": "2009-02-21T01:47:42.000Z",
  "updated": "2009-08-06T00:34:24.000Z",
  "title": "Revisiting the \"Fundamental Plane\" of Black Hole Activity at Extremely Low Luminosities",
  "authors": [
    "Feng Yuan",
    "Zhaolong Yu",
    "Luis C. Ho"
  ],
  "comment": "24 pages, 2 tables, 3 figures; accepted by ApJ",
  "journal": "Astrophys.J.703:1034-1043,2009",
  "doi": "10.1088/0004-637X/703/1/1034",
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA"
  ],
  "abstract": "We investigate the origin of the X-ray emission in low-luminosity AGNs (LLAGNs). Yuan & Cui (2005) predicted that the X-ray emission should originate from jets rather than from an advection-dominated accretion flow (ADAF) when the X-ray luminosity $L_{\\rm X}$ of the source is below a critical value of $L_{\\rm X,crit} \\approx 10^{-6}L_{\\rm Edd}$. This prediction implies that the X-ray spectrum in such sources should be fitted by jets rather than ADAFs. Furthermore, below $L_{\\rm X,crit}$ the correlation between radio ($L_{\\rm R}$) and X-ray ($L_{\\rm X}$) luminosities and the black hole mass ($M$)--the so-called fundamental plane of black hole activity--should deviate from the general correlation obtained by Merloni, Heinz & Di Matteo (2003) and become steeper. The Merloni et al. correlation is described by ${\\rm log}L_{\\rm R} =0.6{\\rm log}L_{\\rm X}+0.78{\\rm log}M+7.33$, while the predicted correlation is ${\\rm log}L_{\\rm R}=1.23{\\rm log}L_{\\rm X} +0.25{\\rm log}M-13.45$. We collect data from the literature to check the validity of these two expectations. We find that among the 16 LLAGNs with good X-ray and radio spectra, 13 are consistent with the Yuan & Cui prediction. For the 22 LLAGNs with $L_{\\rm X} < L_{\\rm X,crit}$, the fundamental plane correlation is described by ${\\rm log}L_{\\rm R}=1.22{\\rm log}L_{\\rm X}+0.23{\\rm log}M-12.46 $, also in excellent agreement with the prediction.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2009-08-06T00:34:24.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "luminosity",
      "extremely low luminosities",
      "black hole activity-should deviate",
      "x-ray emission",
      "fundamental plane correlation"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "The Astrophysical Journal",
      "year": 2009,
      "month": "Sep",
      "volume": 703,
      "number": 1,
      "pages": 1034
    },
    "note": {
      "typesetting": "TeX",
      "pages": 24,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 813908,
      "adsabs": "2009ApJ...703.1034Y"
    }
  }
}