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arXiv · 0908.0891

On the electron energy distribution index of Swift Gamma-Ray Burst Afterglows

P. A. Curran·P. A. Evans·M. de Pasquale·M. J. Page·A. J. van der Horst
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Abstract

The electron energy distribution index, p, is a fundamental parameter of the synchrotron emission from a range of astronomical sources. Here we examine one such source of synchrotron emission, Gamma-Ray Burst afterglows observed by the Swift satellite. Within the framework of the blast wave model, we examine the constraints placed on the distribution of p by the observed X-ray spectral indices and parametrise the distribution. We find that the observed distribution of spectral indices are inconsistent with an underlying distribution of p composed of a single discrete value but consistent with a Gaussian distribution centred at p = 2.36 and having a width of 0.59. Furthermore, accepting that the underlying distribution is a Gaussian, we find the majority (>94%) of GRB afterglows in our sample have cooling break frequencies less than the X-ray frequency.

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P. A. Curran, P. A. Evans, M. de Pasquale, M. J. Page, A. J. van der Horst. 2010-05-25. On the electron energy distribution index of Swift Gamma-Ray Burst Afterglows. https://doi.org/10.1088/2041-8205%2F716%2F2%2Fl135

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