{
  "id": "1705.07901",
  "version": "v1",
  "published": "2017-05-22T18:00:01.000Z",
  "updated": "2017-05-22T18:00:01.000Z",
  "title": "Discovery of a Luminous Radio Transient 460 pc from the Central Supermassive Black Hole in Cygnus A",
  "authors": [
    "Daniel A. Perley",
    "Richard A. Perley",
    "Vivek Dhawan",
    "Christopher L. Carilli"
  ],
  "comment": "10 pages, 4 figures, accepted to ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We report the appearance of a new radio source at a projected offset of 460 pc from the nucleus of Cygnus A. The flux density of the source (which we designate Cygnus A-2) rose from an upper limit of <0.5 mJy in 1989 to 4 mJy in 2016 (nu=8.5 GHz), but is currently not varying by more than a few percent per year. The radio luminosity of the source is comparable to the most luminous known supernovae, it is compact in VLBA observations down to a scale of 4 pc, and it is coincident with a near-infrared point source seen in pre-existing adaptive optics and HST observations. The most likely interpretation of this source is that it represents a secondary supermassive black hole in a close orbit around the Cygnus A primary, although an exotic supernova model cannot be ruled out. The gravitational influence of a secondary SMBH at this location may have played an important role in triggering the rapid accretion that has powered the Cygnus A radio jet over the past 10^7 years.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-05-22T18:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "central supermassive black hole",
      "luminous radio transient",
      "exotic supernova model",
      "secondary supermassive black hole",
      "vlba observations"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}