Spectral fits to the data from the HGPS source for which the most (upper panel) and least (lower panel) constraining lower limit on E_cut,  h is derived. Shown in green are the best fits to the data with a power-law spectrum. Red lines are best fits to the data with a γ-ray power-law spectrum with exponential cutoff at the lower limit E_cut,  γ derived from the HGPS data. Yellow lines are the corresponding best fits to the data in a hadronic model with cutoff at the lower limit E_cut,  h. Limits for the lower plot are at 90% CL. In the upper panel, best fits with lower cutoff limit at 90% CL are hardly distinguishable from the best power-law fit. Therefore, 99% CL best fits are shown in this case.