{
  "id": "2103.00332",
  "version": "v1",
  "published": "2021-02-27T21:33:56.000Z",
  "updated": "2021-02-27T21:33:56.000Z",
  "title": "Hubble Space Telescope observations of the old pulsar PSR J0108-1431",
  "authors": [
    "Vadim Abramkin",
    "Yuriy Shibanov",
    "Roberto P. Mignani",
    "George G. Pavlov"
  ],
  "comment": "14 pages, 7 figures, 7 tables. Accepted to ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We present results of optical-UV observations of the 200 Myr old rotation-powered radio pulsar J0108$-$1431 with the Hubble Space Telescope. We found a putative candidate for the far-UV (FUV) pulsar counterpart, with the flux density $f_\\nu = 9.0\\pm 3.2$ nJy at $\\lambda = 1528$ \\AA. The pulsar was not detected, however, at longer wavelengths, with $3\\sigma$ upper limits of 52, 37, and 87 nJy at $\\lambda =$ 4326, 3355, and 2366 \\AA, respectively. Assuming that the pulsar counterpart was indeed detected in FUV, and the previously reported marginal $U$ and $B$ detections with the Very Large Telescope were real, the optical-UV spectrum of the pulsar can be described by a power-law model with a nearly flat $f_\\nu$ spectrum. Similar to younger pulsars detected in the optical, the slope of the nonthermal spectrum steepens in the X-ray range. The pulsar's luminosity in the 1500--6000 \\AA wavelength range, $L \\sim 1.2\\times 10^{27} (d/210\\,{\\rm pc})^2$ erg s$^{-1}$, corresponds to a high efficiency of conversion of pulsar rotation energy loss rate $\\dot {E}$ to the optical-UV radiation, $\\eta = L/\\dot{E} \\sim (1$--$6)\\times 10^{-4}$, depending on somewhat uncertain values of distance and spectral slope. The brightness temperature of the bulk neutron star surface does not exceed 59,000 K ($3\\sigma$ upper bound), as seen by a distant observer. If we assume that the FUV flux is dominated by a thermal component, then the surface temperature can be in the range of 27,000--55,000 K, requiring a heating mechanism to operate in old neutron stars.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-02-27T21:33:56.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hubble space telescope observations",
      "old pulsar psr",
      "old rotation-powered radio pulsar",
      "rotation-powered radio pulsar j0108",
      "pulsar rotation energy loss rate"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}