{
  "id": "1607.00416",
  "version": "v1",
  "published": "2016-07-01T21:45:27.000Z",
  "updated": "2016-07-01T21:45:27.000Z",
  "title": "Radio Constraints on Long-Lived Magnetar Remnants in Short Gamma-Ray Bursts",
  "authors": [
    "Wen-fai Fong",
    "Brian D. Metzger",
    "Edo Berger",
    "Feryal Ozel"
  ],
  "comment": "9 pages, 4 figures, 2 tables. Submitted to ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The merger of a neutron star binary may result in the formation of a rapidly-spinning magnetar. The magnetar can potentially survive for seconds or longer as a supramassive neutron star before collapsing to a black hole if, indeed, it collapses at all. During this process, a fraction of the magnetar's rotational energy of ~10^53 erg is transferred via magnetic spin-down to the surrounding ejecta. The resulting interaction between the ejecta and the surrounding circumburst medium powers a >year-long synchrotron radio transient. We present a search for radio emission with the Very Large Array following nine short-duration gamma-ray bursts (GRBs) at rest-frame times of ~1.3-7.6 years after the bursts, focusing on those events which exhibit early-time excess X-ray emission that may signify the presence of magnetars. We place upper limits of <18-32 microJy on the 6.0 GHz radio emission, corresponding to spectral luminosities of <(0.05-8.3)x10^39 erg s^-1. Comparing these limits to the predicted radio emission from a long-lived remnant and incorporating measurements of the circumburst densities from broad-band modeling of short GRB afterglows, we rule out a stable magnetar with an energy of 10^53 erg for half of the events in our sample. A supramassive remnant that injects a lower rotational energy of 10^52 erg is ruled out for a single event, GRB 050724A. This study represents the deepest and most extensive search for long-term radio emission following short GRBs to date, and thus the most stringent limits placed on the physical properties of magnetars associated with short GRBs from radio observations.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-07-01T21:45:27.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "short gamma-ray bursts",
      "long-lived magnetar remnants",
      "radio constraints",
      "radio emission",
      "short grb"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}