{
  "id": "2302.00204",
  "version": "v1",
  "published": "2023-02-01T03:16:59.000Z",
  "updated": "2023-02-01T03:16:59.000Z",
  "title": "Observational connection of non-thermal X-ray emission from pulsars with their timing properties and thermal emission",
  "authors": [
    "Hsiang-Kuang Chang",
    "Jr-Yue Hsiang",
    "Che-Yen Chu",
    "Yun-Hsin Chung",
    "Tze-Hsiang Su",
    "Tzu-Hsuan Lin",
    "Chien-You Huang"
  ],
  "comment": "13 pages, 11 figures, accepted by MNRAS",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The origin and radiation mechanisms of high energy emissions from pulsars have remained mysterious since their discovery. Here we report, based on a sample of 68 pulsars, observational connection of non-thermal X-ray emissions from pulsars with their timing properties and thermal emissions, which may provide some constraints on theoretical modeling. Besides strong correlations with the spin-down power $\\dot{E}$ and the magnetic field strength at the light cylinder $B_{\\rm lc}$, the non-thermal X-ray luminosity in 0.5 - 8 keV, $L_{\\rm p}$, represented by the power-law component in the spectral model, is found to be strongly correlated with the highest possible electric field strength in the polar gap, $E_{\\rm pc}$, of the pulsar. The spectral power index $\\Gamma_{\\rm p}$ of that power-law component is also found, for the first time in the literature, to strongly correlate with $\\dot{E}$, $B_{\\rm lc}$ and $E_{\\rm pc}$, thanks to the large sample. In addition, we found that $L_{\\rm p}$ can be well described by $L_{\\rm p}\\propto T^{5.96\\pm 0.64}R^{2.24\\pm 0.18}$, where $T$ and $R$ are the surface temperature and the emitting-region radius of the surface thermal emission, represented by the black-body component in the spectral model. $\\Gamma_{\\rm p}$, on the other hand, can be well described only when timing variables are included, and the relation is $\\Gamma_{\\rm p} = \\log(T^{-5.8\\pm 1.93}R^{-2.29\\pm 0.85}P^{-1.19\\pm 0.88}\\dot{P}^{0.94\\pm 0.44})$ plus a constant. These relations strongly suggest the existence of connections between surface thermal emission and electron-positron pair production in pulsar magnetospheres.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-02-01T03:16:59.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "non-thermal x-ray emission",
      "observational connection",
      "timing properties",
      "surface thermal emission",
      "spectral model"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}