Testing the blast wave model with Swift GRBs

We can successfully interpret all of the bursts in our multi-wavelength sample of 10, except two, within the framework of the blast wave model, and we can estimate with confidence the electron energy distribution index for 6 of the sample. Furthermore we identify jet breaks in almost half of the bursts. The values of k suggest that the circumburst density profiles are not drawn from only one of the constant density or wind-like media populations. A statistical analysis of the distribution of p reveals that, even in the most conservative case of least scatter, the values are not consistent with a single, universal value. This is in agreement with our results for a larger sample of X-ray only afterglows which we summarise here.