{
  "id": "2103.13657",
  "version": "v1",
  "published": "2021-03-25T08:12:26.000Z",
  "updated": "2021-03-25T08:12:26.000Z",
  "title": "Unveiling the broadband spectral and temporal properties of PKS\\,0903-57 during its brightest flare",
  "authors": [
    "Zahir Shah",
    "V. Jithesh",
    "S. Sahayanathan",
    "Naseer Iqbal"
  ],
  "comment": "14 pages, 11 figures, 5 Tables. Accepted for publication in MNRAS",
  "doi": "10.1093/mnras/stab834",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We carried a detailed spectral and temporal study of blazar, \\mbox{PKS\\,0903-57} using the \\emph{Fermi}-LAT and \\emph{Swift}-XRT/UVOT observations, during its brightest flaring period MJD\\,58931--58970. During this period, the maximum daily averaged $\\gamma$-ray flux ($\\rm F_{0.1-500\\,GeV}$) of $\\rm9.42\\times10^{-6}\\,ph\\,cm^{-2}\\,s^{-1}$ is observed on MJD\\,58951.5, the highest $\\gamma$-ray flux detected from \\mbox{PKS\\,0903-57} till now. Several high-energy (HE) photons ($>\\,10$\\,GeV) consistent with the source location at high probability (>\\,99\\%) are detected, and the $\\gamma$-ray lightcurve in the active state shows multiple substructures with asymmetric profile. In order to understand the possible physical scenario responsible for the flux enhancement, we carried a detailed broadband spectral study of \\mbox{PKS\\,0903-57} by choosing different flux states from its active period. Neglecting the multi-band variability in each of the selected time intervals, we could reproduce their averaged broadband SEDs with a one-zone leptonic model whose parameters were derived with a $\\chi^2$-fit. We found that the broadband SED during different flux states can be reproduced by the synchrotron, synchrotron-self-Compton (SSC) and External-Compton (EC) processes. The seed photons for EC process from BLR or IR torus provide acceptable fits to the GeV spectrum in all the flux states; however, the detection of HE photons together with the equipartition condition suggest that the EC/IR process is a more likely scenario. Further, a detailed comparison between the fit parameters shows that the flux enhancement from quiescent-state to the flaring-state is mostly related to increase in the bulk Lorentz factor of the emission region and change in the break energy of the source spectrum.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-03-25T08:12:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "temporal properties",
      "brightest flare",
      "flux states",
      "flux enhancement",
      "ray flux"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}