{
  "id": "2103.06548",
  "version": "v1",
  "published": "2021-03-11T09:19:06.000Z",
  "updated": "2021-03-11T09:19:06.000Z",
  "title": "Fast Blue Optical Transients due to Circumstellar Interaction and the Mysterious SN 2018gep",
  "authors": [
    "Shing-Chi Leung",
    "Jim Fuller",
    "Ken'ichi Nomoto"
  ],
  "comment": "19 pages, 28 figures, submitted to Astrophysical Journal at 10 March 2021",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The discovery of SN 2018gep (ZTF18abukavn) challenged our understanding of the late-phase evolution of massive stars and their supernovae (SNe). The fast rise in luminosity of this SN (spectroscopically classified as a broad-lined Type Ic SN), indicates that the ejecta interacts with a dense circumstellar medium (CSM), while an additional energy source such as $^{56}$Ni-decay is required to explain the late-time light curve. These features hint at the explosion of a massive star with pre-supernova mass-loss. In this work, we examine the physical origins of rapidly evolving astrophysical transients like SN 2018gep. We investigate the wave-driven mass-loss mechanism and how it depends on model parameters such as progenitor mass and deposition energy, searching for stellar progenitor models that can reproduce the observational data. A model with an ejecta mass $\\sim \\! 2 \\, M_{\\odot}$, explosion energy $\\sim \\! 10^{52}$ erg, a circumstellar medium of mass $\\sim \\! 0.3 \\, M_{\\odot}$ and radius $\\sim \\! 1000 \\, R_{\\odot}$, and a $^{56}$Ni mass of $\\sim \\! 0.3 \\, M_{\\odot}$ provides a good fit to the bolometric light curve. We also examine how interaction-powered light curves depend more generally on these parameters, and how ejecta velocities can help break degeneracies. We find both wave-driven mass-loss and mass ejection via pulsational pair-instability can plausibly create the dense CSM in SN 2018gep, but we favor the latter possibility.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-03-11T09:19:06.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "fast blue optical transients",
      "mysterious sn 2018gep",
      "circumstellar interaction",
      "light curve",
      "wave-driven mass-loss"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}