{
  "id": "1404.0899",
  "version": "v1",
  "published": "2014-04-03T13:19:23.000Z",
  "updated": "2014-04-03T13:19:23.000Z",
  "title": "Warm absorbers in X-rays (WAX), a comprehensive high resolution grating spectral study of a sample of Seyfert galaxies: I. A global view and frequency of occurrence of warm absorbers",
  "authors": [
    "Sibasish Laha",
    "Matteo Guainazzi",
    "Gulab C. Dewangan",
    "Susmita Chakravorty",
    "Ajit K. Kembhavi"
  ],
  "comment": "Accepted for publication in the MNRAS",
  "categories": [
    "astro-ph.HE",
    "astro-ph.CO",
    "astro-ph.GA"
  ],
  "abstract": "We present results from a homogeneous analysis of the broadband 0.3-10 keV CCD resolution as well as of soft X-ray high-resolution grating spectra of a hard X-ray flux-limited sample of 26 Seyfert galaxies observed with XMM-Newton. Our goal is to characterise the warm absorber (WA) properties along the line-of-sight to the active nucleus. We significantly detect WAs in $65\\%$ of the sample sources. Our results are consistent with WAs being present in at least half of the Seyfert galaxies in the nearby Universe, in agreement with previous estimates . We find a gap in the distribution of the ionisation parameter in the range $0.5<\\log\\xi<1.5$ which we interpret as a thermally unstable region for WA clouds. This may indicate that the warm absorber flow is probably constituted by a clumpy distribution of discrete clouds rather than a continuous medium. The distribution of the WA column densities for the sources with broad Fe K$\\alpha$ lines are similar to those sources which do not have broadened emission lines. Therefore the detected broad Fe K$\\alpha$ emission lines are bonafide and not artifacts of ionised absorption in the soft X-rays. The WA parameters show no correlation among themselves, with the exception of the ionisation parameter versus column density. The shallow slope of the $\\log\\xi$ versus $\\log v_{\\rm out}$ linear regression ($0.12\\pm 0.03$) is inconsistent with the scaling laws predicted by radiation or magneto-hydrodynamic-driven winds. Our results suggest also that WA and Ultra Fast Outflows (UFOs) do not represent extreme manifestation of the same astrophysical system.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-04-03T13:19:23.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "warm absorber",
      "high resolution grating spectral study",
      "comprehensive high resolution grating spectral",
      "seyfert galaxies",
      "global view"
    ],
    "publication": {
      "doi": "10.1093/mnras/stu669",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2014,
      "month": "Jul",
      "volume": 441,
      "number": 3,
      "pages": 2613
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1288461,
      "adsabs": "2014MNRAS.441.2613L"
    }
  }
}