{
  "id": "1105.4761",
  "version": "v1",
  "published": "2011-05-24T13:37:11.000Z",
  "updated": "2011-05-24T13:37:11.000Z",
  "title": "The non-thermal, time-variable radio emission from Cyg OB2 # 5: A wind-collision region",
  "authors": [
    "Gisela Ortiz-Leon",
    "Laurent Loinard",
    "Luis F. Rodriguez",
    "Amy J. Mioduszewski",
    "Sergio A. Dzib"
  ],
  "comment": "Accepted for publication in The Astrophysical Journal",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "The radio emission from the well-studied massive stellar system Cyg OB2 #5 is known to fluctuate with a period of 6.7 years between a low-flux state when the emission is entirely of free-free origin, and a high-flux state when an additional non-thermal component (of hitherto unknown nature) appears. In this paper, we demonstrate that the radio flux of that non-thermal component is steady on timescales of hours, and that its morphology is arc-like. This shows that the non-thermal emission results from the collision between the strong wind driven by the known contact binary in the system, and that of an unseen companion on a somewhat eccentric orbit with a 6.7-yr period and a 5 to 10 mas semi-major axis. Together with the previously reported wind-collision region located about 0.8 arcsec to the north-east of the contact binary, Cyg OB2 #5 appears to be the only multiple system known so far to harbor two radio-imaged wind-collision regions.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-05-24T13:37:11.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "wind-collision region",
      "time-variable radio emission",
      "massive stellar system cyg ob2",
      "non-thermal component",
      "contact binary"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/737/1/30",
      "journal": "The Astrophysical Journal",
      "year": 2011,
      "month": "Aug",
      "volume": 737,
      "number": 1,
      "pages": 30
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 901128,
      "adsabs": "2011ApJ...737...30O"
    }
  }
}