Are short γ-ray bursts collimated? GRB 050709, a flare but no break

  title={Are short $\gamma$-ray bursts collimated? GRB 050709, a flare but no break},
  author={Darach J. Watson and Jens Hjorth and P. Jakobsson and D. W. Xu and J. P. U. Fynbo and Jesper Sollerman and Christina C. Thone and Kristian Pedersen},
  journal={Astronomy and Astrophysics},
Context. From the small sample of afterglow lightcurves of short duration γ -ray bursts (GRBs), the decays are rapid, roughly following a power-law in time. It has been assumed that the afterglow emission in short GRBs is collimated in jets in the same way as in long GRBs. Aims. An achromatic break in a short GRB afterglow lightcurve would therefore be strong evidence in favour of collimation in short GRBs. Methods. We examine the optical lightcurve of the afterglow of the short GRB 050709, the… Expand

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