Upper left panel: image of the RoI obtained by integrating the binned cube of measured counts over the energy axis (E > 2 TeV), and correlating it with a 0.1°-radius top-hat kernel. The hatched regions were excluded from the likelihood computation. The bright area around l ≳ 345° results from deep observations of RX J1713-3946 and HESS J1708-410. Upper right panel: energy-integrated (E > 2 TeV) map of model-predicted counts, with names and 1σ shapes of all model components overlaid. The large-scale discarded component is indicated by the dashed circle – see the main text for more details. Lower left panel: spatial distribution of model residuals, showing the statistical significance – in units of Gaussian standard deviations – of counts – model fluctuations. The image was obtained assuming Cash statistic for Poisson-distributed signals with perfectly known background model (Cash 1979). Lower right panel: histogram containing the number of occurrences of each significance value (assuming Cash statistic), from the lower left panel. The adjustment of a Gaussian function to the histogram is shown, together with a reference standard normal distribution.