Upper boxes show the H.E.S.S. energy flux spectra of HESS J1534−571, HESS J1614−518, and HESS J1912+101 (blue data points with 1 σ statistical uncertainties), respectively. The bin size is determined by the requirement of at least 2σ significance per bin. The solid blue lines with the gray butterflies (1 σ error of the fit) show the best fit power-law models from Table 4. The Bottom boxes show the deviation from the respective model in units of sigma, calculated as (F − F_model)∕σ_F. Systematic errors do not permit the application of more complex models to describe the data.