{
  "id": "1710.05869",
  "version": "v1",
  "published": "2017-10-16T17:02:13.000Z",
  "updated": "2017-10-16T17:02:13.000Z",
  "title": "GRB 170817A: a short GRB seen off-axis",
  "authors": [
    "Xin-Bo He",
    "Pak-Hin Thomas Tam",
    "Rong-Feng Shen"
  ],
  "comment": "7 pages, 4 figures",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The leading theory for short-duration GRBs ($\\lesssim$ 2s) is neutron star-neutron star (NS-NS) mergers or black hole-NS mergers, while bursts of soft gamma-ray repeaters (SGRs) in a nearby galaxy may mimic a short GRB. If a short GRB due to a merger occur in the local Universe (i.e., redshift $\\le$ {0.1-0.2}), the merger event can simultaneously produce gravitational wave signal detectable by current detectors like advanced LIGO/Virgo, while no detectable signal is expected for an SGR. Recently, Fermi GBM detected a short GRB~170817A. It is reported to have a redshift of 0.0098. Assuming this is true, it will have two profound implications: (1) the isotropic-equivalent $\\gamma$-ray energetics, E$_{iso,\\gamma}$, of GRB~170817A is only about 4 $\\times$ 10$^{46}$ erg, much lower than a typical cosmological short GRB whose E$_{iso,\\gamma}$ is $\\gtrsim10^{50}$erg. So it will be the first low-luminosity GRB of short duration. An interesting explanation is that it is an off-axis short GRB with structured jets; and (2) given its proximity, the GW signal of a merger should have been detected by advanced LIGO/Virgo.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-10-16T17:02:13.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "grb 170817a",
      "simultaneously produce gravitational wave signal",
      "off-axis short grb",
      "produce gravitational wave signal detectable",
      "first low-luminosity grb"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}