Left panel: time-averaged VHE spectrum measured from the direction of 1RXS J101015.9 − 311909. The bow-tie represents 1σ confidence level error band of the fitted spectrum using a power-law hypothesis. The lower panel shows the fit residuals, i.e. (N_γ − N_theo)/N_theo, where N_γ and N_theo are the detected and expected number of excess events, respectively. Right panel: Fermi/LAT and H.E.S.S. bow-ties. The two Fermi/LAT bow-ties represent the E_th > 300   MeV (dotted line) and the E_th > 1   GeV (dashed line) spectral results. All the bow-ties (H.E.S.S. and Fermi/LAT) result from a forward-folding spectral analysis technique.