{
  "id": "1705.10797",
  "version": "v1",
  "published": "2017-05-30T18:00:02.000Z",
  "updated": "2017-05-30T18:00:02.000Z",
  "title": "The cocoon emission - an electromagnetic counterpart to gravitational waves from neutron star mergers",
  "authors": [
    "Ore Gottlieb",
    "Ehud Nakar",
    "Tsvi Piran"
  ],
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Short Gamma-Ray Bursts (SGRBs) are believed to arise from compact binary mergers (either neutron star-neutron star or black hole-neutron star). If so their jets must penetrate outflows that are ejected during the merger. As a jet crosses the ejecta it dissipates its energy, producing a hot cocoon which surrounds it. We present here 3D numerical simulations of jet propagation in mergers' outflows and we calculate the resulting emission. This emission consists of two components: the cooling emission, the leakage of the thermal energy of the hot cocoon, and the cocoon macronova that arises from the radioactive decay of the cocoon's material. This emission gives a brief (~ one hour) blue, wide angle signal. While the parameters of the outflow and jet are uncertain, for the configurations we have considered the signal is bright (~ -14 $-$ -15 absolute magnitude) and outshines all other predicted UV-optical signals. The signal is brighter when the jet breakout time is longer and its peak brightness does not depend strongly on the highly uncertain opacity. A rapid search for such a signal is a promising strategy to detect an electromagnetic merger counterpart. A detected candidate could be then followed by deep IR searches for the longer but weaker macronova arising from the rest of the ejecta.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-05-30T18:00:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "neutron star mergers",
      "cocoon emission",
      "gravitational waves",
      "electromagnetic counterpart",
      "hot cocoon"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}