{
  "id": "1612.07083",
  "version": "v1",
  "published": "2016-12-21T12:58:29.000Z",
  "updated": "2016-12-21T12:58:29.000Z",
  "title": "Search for transitions between states in redbacks and black widows using seven years of Fermi-LAT observations",
  "authors": [
    "Diego F. Torres",
    "Long Ji",
    "Jian Li",
    "Alessandro Papitto",
    "Nanda Rea",
    "Emma de Ona Wilhelmi",
    "Shu Zhang"
  ],
  "comment": "20 pages, 3 figures, 2 tables. Accepted for publication in ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Considering about seven years of Fermi-Large Area Telescope (LAT) data, we present a systematic search for variability possibly related to transitions between states in redbacks and black widow systems. Transitions are characterized by sudden and significant changes in the gamma-ray flux that persist on a timescale much larger than the orbital period. This phenomenology was already detected in the case of two redback systems, PSR J1023+0038 and PSR J1227-4853, for which we present here a dedicated study. We show the existence of only one transition for each of these systems over the past seven years. We determine their spectra, establishing high-energy cutoffs at a few GeV for the high gamma-ray state of PSR J1023+0038 and for both states of PSR J1227-4853. The surveying capability of the Fermi-LAT allows studying whether similar phenomenology has occurred in other sources. Although we have not found any hint for a state transition for most of the studied pulsars, we note two black-widow systems, PSR J2234+0944 and PSR J1446-4701, whose apparent variability is reminiscent of the transitions in PSR J1023+0038 and PSR J1227-4853. For the other systems we set limits on potential transitions in their measured gamma-ray light curves.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-12-21T12:58:29.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "transition",
      "fermi-lat observations",
      "black widow systems",
      "fermi-large area telescope",
      "high gamma-ray state"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 20,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}