Distribution of models with p-value >0.003, presented as a violin plot, illustrating the kernel probability density. The width of the shaded area represents the proportion of number of fits located at these positions. The upper and lower bars represent the maximum and minimum values. Top: Fitted energy cut-off distribution as a function of injection index for the combined H.E.S.S. and HAWC dataset. The red horizontal line shows the value of energy cut-off chosen for the fixed E_c fit. Bottom: distribution of the fitted diffusion coefficient in the case of E_c = 1 PeV and E_c left free to vary, for a combined fit to H.E.S.S. and HAWC data. Solid lines indicate the value ranges for the B/C diffusion coefficient and the statistical uncertainty of HAWC diffusion coefficient obtained in Abeysekara et al. (2017a).