{
  "id": "1510.01111",
  "version": "v1",
  "published": "2015-10-05T11:57:14.000Z",
  "updated": "2015-10-05T11:57:14.000Z",
  "title": "Quasi periodic oscillations in active galactic nuclei",
  "authors": [
    "William Alston",
    "Andy Fabian",
    "Julija Markeviciute",
    "Michael Parker",
    "Matt Middleton",
    "Erin Kara"
  ],
  "comment": "Proceedings for The Extremes of Black Hole Accretion, Madrid, 2015. To appear in Astronomische Nachrichten, 6 pages, 4 figures",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Quasi-periodic oscillations (QPOs) are coherent peaks of variability power observed in the X-ray power spectra (PSDs) of stellar mass X-ray binaries (XRBs). A scale invariance of the accretion process implies they should be present in the active galactic nuclei. The first robust detection was a $\\sim 1$ hr periodicity in the Seyfert galaxy RE J1034+396 from a $\\sim 90$ ks XMM-Newton observation, however, subsequent observations failed to detect the QPO in the $0.3-10.0$ keV band. In this talk we present the recent detection of the $\\sim 1$ hr periodicity in the $1.0-4.0$ keV band of 4 further low-flux/spectrally-harder observations of RE J1034+396 (see Alston et al 2014). We also present recent work on the discovery of a QPO in the Seyfert galaxy, MS 22549-3712, which again is only detected in energy bands associated with the primary power-law continuum emission (Alston et al 2015). We conclude these features are most likely analogous to the high-frequency QPOs observed in XRBs. In both sources, we also see evidence for X-ray reverberation at the QPO frequency, where soft X-ray bands and Iron K$\\alpha$ emission lag the primary X-ray continuum. These time delays may provide another diagnostic for understanding the underlying QPO mechanism observed in accreting black holes.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-10-05T11:57:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "active galactic nuclei",
      "quasi periodic oscillations",
      "seyfert galaxy",
      "kev band",
      "primary power-law continuum emission"
    ],
    "publication": {
      "doi": "10.1002/asna.201612323"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1396095
    }
  }
}