{
  "id": "1109.4143",
  "version": "v1",
  "published": "2011-09-19T20:00:01.000Z",
  "updated": "2011-09-19T20:00:01.000Z",
  "title": "A variable mid-infrared synchrotron break associated with the compact jet in GX 339-4",
  "authors": [
    "P. Gandhi",
    "A. W. Blain",
    "D. M. Russell",
    "P. Casella",
    "J. Malzac",
    "S. Corbel",
    "P. D'Avanzo",
    "F. W. Lewis",
    "S. Markoff",
    "M. Cadolle Bel",
    "P. Goldoni",
    "S. Wachter",
    "D. Khangulyan",
    "A. Mainzer"
  ],
  "comment": "ApJL vol. 740, issue 1, L11",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Many X-ray binaries remain undetected in the mid-infrared, a regime where emission from their compact jets is likely to dominate. Here, we report the detection of the black hole binary GX 339-4 with the Wide-field Infrared Survey Explorer (WISE) during a very bright, hard accretion state in 2010. Combined with a rich contemporaneous multiwavelength dataset, clear spectral curvature is found in the infrared, associated with the peak flux density expected from the compact jet. An optically-thin slope of ~-0.7 and a jet radiative power of >6x10^{35} erg/s (d/8 kpc)^2 are measured. A ~24 h WISE light curve shows dramatic variations in mid-infrared spectral slope on timescales at least as short as the satellite orbital period ~95 mins. There is also significant change during one pair of observations spaced by only 11 s. These variations imply that the spectral break associated with the transition from self-absorbed to optically-thin jet synchrotron radiation must be varying across the full wavelength range of ~3-22 microns that WISE is sensitive to, and more. Based on four-band simultaneous mid-infrared detections, the break lies at ~5x10^{13} Hz in at least two epochs of observation, consistent with a magnetic field B~1.5x10^4 G assuming a single-zone synchrotron emission region. The observed variability implies that either B, or the size of the acceleration zone above the jet base, are being modulated by factors of ~10 on relatively-short timescales.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-09-19T20:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "variable mid-infrared synchrotron break",
      "compact jet",
      "single-zone synchrotron emission region",
      "black hole binary gx",
      "optically-thin jet synchrotron radiation"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/2041-8205/740/1/L13",
      "journal": "The Astrophysical Journal",
      "year": 2011,
      "month": "Oct",
      "volume": 740,
      "number": 1
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 927942,
      "adsabs": "2011ApJ...740L..13G"
    }
  }
}