The outflow structure of GW170817 from late-time broad-band observations

E. Troja, L. Piro, Geoffrey Scott Ryan, Hendrik Van Eerten, R Ricci, M. H. Wieringa, S. Lotti, T. Sakamoto, S. B. Cenko

Research output: Contribution to journalArticlepeer-review

186 Citations (SciVal)


We present our broad-band study of GW170817 from radio to hard X-rays, including NuSTAR and Chandra observations up to 165 d after the merger, and a multimessenger analysis including LIGO constraints. The data are compared with predictions from a wide range of models, providing the first detailed comparison between non-trivial cocoon and jet models. Homogeneous and power-law shaped jets, as well as simple cocoon models are ruled out by the data, while both a Gaussian shaped jet and a cocoon with energy injection can describe the current data set for a reasonable range of physical parameters, consistent with the typical values derived from short GRB afterglows. We propose that these models can be unambiguously discriminated by future observations measuring the post-peak behaviour, with F v ∝ t ~-1.0 for the cocoon and F v ∝ t ~-2.5 for the jet model.

Original languageEnglish
Pages (from-to)L18-L23
Number of pages5
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date13 Apr 2018
Publication statusPublished - 21 Jul 2018


  • Gamma-ray burst
  • Gamma-ray burst: general
  • Gravitational waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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