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arXiv · 1801.06516

The outflow structure of GW170817 from late time broadband observations

E. Troja·L. Piro·G. Ryan·H. van Eerten·R. Ricci·M. H. Wieringa·S. Lotti·T. Sakamoto·S. B. Cenko
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Abstract

We present our broadband study of GW170817 from radio to hard X-rays, including NuSTAR and Chandra observations up to 165 days after the merger, and a multi-messenger 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 dataset 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 slope -1.0 for the cocoon and -2.5 for the jet model.

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E. Troja, L. Piro, G. Ryan, H. van Eerten, R. Ricci, M. H. Wieringa, S. Lotti, T. Sakamoto, S. B. Cenko. 2018-01-19. The outflow structure of GW170817 from late time broadband observations. https://doi.org/10.1093/mnrasl/sly061

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