{
  "id": "2407.07047",
  "version": "v1",
  "published": "2024-07-09T17:09:30.000Z",
  "updated": "2024-07-09T17:09:30.000Z",
  "title": "The First VHE Activity of OJ 287 and the Extragalactic Background Light",
  "authors": [
    "Sameer Yadav",
    "Pankaj Kushwaha"
  ],
  "comment": "13 pages, 4 figures, 2 tables",
  "journal": "Galaxies 2024, 12(4), 34",
  "doi": "10.3390/galaxies12040034",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The BL Lacertae (BL Lac) object OJ 287 underwent an intense X-ray activity phase, exhibiting its brightest recorded X-ray flare in 2016-2017, characterized by much softer X-ray spectra and, concurrently, its first-ever recorded very-high-energy (VHE) emission (100--560 GeV), reported by the VERITAS observatory. Broadband spectral energy distribution reveals a new jet emission component similar to high-synchrotron-peaked BL Lac objects, thereby implying the soft X-ray spectrum for the synchrotron emission. Using the advantage of simultaneous X-ray and VHE spectral information, as well as the source being a low-synchrotron-peaked BL Lac object, we systematically explored the extragalactic background light (EBL) spectrum by demanding that the VHE spectrum cannot be harder than the X-ray spectrum. We used three different phenomenological forms of the EBL spectral shape (power-law, parabola, and polynomial) motivated by current constraints on the EBL with the Bayesian Monte Carlo approach to infer the credible EBL range. Our study favors an almost flat power-law spectral shape and is consistent with previous studies. The other spectral forms capable of capturing curvature though result in a better statistics value; the improvement is statistically insignificant given the additional parameters.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-07-09T17:09:30.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "extragalactic background light",
      "first vhe activity",
      "bl lac object",
      "x-ray spectrum",
      "flat power-law spectral shape"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}