Change (in the comparison with the point source) of the TS value attributed to the GC modelled as a disk of certain radius. The increase of −ΔTS corresponds to the overall worsening of the fit. The change of −ΔTS by 9 corresponds to the 3σ upper limit on the size of the disk. The flux, attributed to the disk is shown with red points with errorbars. Bottom left panel: spectra of 1° radius template of the GC, and GC as a point source. Bottom right panel: 3σ upper limit on the size of the disk as a function of energy. The fit with the power law (R = 0.44°(E/ 1 GeV)^-0.35) is shown with green dot-dashed line.