{
  "id": "1505.00916",
  "version": "v1",
  "published": "2015-05-05T08:38:31.000Z",
  "updated": "2015-05-05T08:38:31.000Z",
  "title": "Multiwavelength behaviour of the blazar OJ 248 from radio to γ-rays",
  "authors": [
    "M. I. Carnerero",
    "C. M. Raiteri",
    "M. Villata",
    "J. A. Acosta-Pulido",
    "F. D'Ammando",
    "P. S. Smith",
    "V. M. Larionov",
    "for the GASP-WEBT collaboration"
  ],
  "comment": "16 pages, 20 figures, 2 tables, in press for MNRAS",
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA"
  ],
  "abstract": "We present an analysis of the multiwavelength behaviour of the blazar OJ 248 at z = 0.939 in the period 2006-2013. We use low-energy data (optical, near-infrared, and radio) obtained by 21 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as data from the Swift (optical-UV and X-rays) and Fermi (gamma-rays) satellites, to study flux and spectral variability and correlations among emissions in different bands. We take into account the effect of absorption by the Damped Lyman Alpha intervening system at z = 0.525. Two major outbursts were observed in 2006-2007 and in 2012-2013 at optical and near-IR wavelengths, while in the high-frequency radio light curves prominent radio outbursts are visible peaking at the end of 2010 and beginning of 2013, revealing a complex radio-optical correlation. Cross-correlation analysis suggests a delay of the optical variations after the gamma-ray ones of about a month, which is a peculiar behaviour in blazars. We also analyse optical polarimetric and spectroscopic data. The average polarization percentage P is less than 3 per cent, but it reaches about 19 per cent during the early stage of the 2012-2013 outburst. A vague correlation of P with brightness is observed. There is no preferred electric vector polarisation angle and during the outburst the linear polarization vector shows wide rotations in both directions, suggesting a complex behaviour or structure of the jet and possible turbulence. The analysis of 140 optical spectra acquired at the Steward Observatory reveals a strong Mg II broad emission line with an essentially stable flux of 6.2 e-15 erg cm-2 s-1 and a full width at half-maximum of 2053 km s-1.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-05-05T08:38:31.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "blazar oj",
      "multiwavelength behaviour",
      "electric vector polarisation angle",
      "lyman alpha intervening system",
      "radio light curves prominent radio"
    ],
    "publication": {
      "doi": "10.1093/mnras/stv823"
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1366141
    }
  }
}