{
  "id": "2008.09330",
  "version": "v1",
  "published": "2020-08-21T06:53:31.000Z",
  "updated": "2020-08-21T06:53:31.000Z",
  "title": "Temporal and Spectral Variability of OJ 287 before the April--June 2020 Outburst",
  "authors": [
    "Nibedita Kalita",
    "Alok C. Gupta",
    "Minfeng Gu"
  ],
  "comment": "11 pages, 4 figures, published in the special issue \"X-Ray Flux and Spectral Variability of Blazars\" of Galaxies journal",
  "journal": "Galaxies 2020, 8, 58",
  "doi": "10.3390/galaxies8030058",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We present the results of a temporal and spectral study of the BL Lacertae object OJ 287 in optical, UV, and X-ray bands with observations performed by Swift satellite during September 2019--March 2020. In this period, the source showed moderate variability characterized by variability amplitude of $\\sim$22--31% in all the wavelengths on a short timescale, except the hard X-ray band which was variable by only $\\sim$8%. We observed that the X-ray flux of the source was significantly dominated by the soft photons below $2$ keV. Soft lags of $\\sim$45 days were detected between the optical/UV and soft X-ray emissions, while there is no correlation between the hard X-rays and the lower energy bands indicating the presence of two emission components or electron populations. Although two components contribute to the X-ray emission, most of the 0.3--10 keV spectra were well fitted with an absorbed power-law model which outlines the dominance of synchrotron over inverse Compton (IC) mechanism. The X-ray spectra follow a weak \"softer when brighter\" trend.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-08-21T06:53:31.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "spectral variability",
      "bl lacertae object oj",
      "april-june",
      "lower energy bands",
      "hard x-ray band"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}