Top panels: distribution of electron energy p⁴f ~ p²ψ ~ E²n at momenta pc = 1, 10, 10², 10³ GeV for model 3 at time t = 2.4 × 10⁷ yr. The black star marks the position of the source where electrons get steadily injected with a momentum pc = 10⁻² GeV and the dashed circle is the shock position at t = 2.4 × 10⁷ yr. The coloured crosses mark the positions for which the electron spectra are shown in the bottom panel of this figure. Bottom panel: spectra p⁴f at time t = 2.4 × 10⁷ yr for the six positions marked by the crosses in the top panel of this figure.