Top panels: gamma-ray sky maps at E = 1, 10, 10² and 10³ GeV for model 1 (homogeneous bubble, isotropic diffusion) at time t = 2.4 × 10⁷ yr. The coloured crosses show the directions for which the gamma-ray spectra are shown in the bottom left panel of this figure. The three dots mark the directions where the gradient angular directions are computed and the lines show these directions. The gamma-ray profile along these is shown in the bottom right panel of this figure. Bottom left panel: gamma-ray spectra in the directions marked by the crosses in the top panel of this figure. The data points are from Ackermann et al. (2014), showing the statistical errors only, the shaded band is reflecting the systematic uncertainty. Bottom right panel: angular profiles along the directions shown in the top panel of this figure for gamma-rays in the energy range 10− 500 GeV. The data points are again from Ackermann et al. (2014).