Radial counts profiles and residuals for the MSH 15–52 observations fitted using a source model with an exponentially cut-off power-law spectrum. Red lines represent the total predicted model counts, blue lines the predicted source counts and green lines the predicted background counts. To determine the profiles, the MSH 15–52 observations were stacked in the field-of-view coordinate system; the source counts are located around the offset angle θ = 0.5° under which the source was observed.