The various velocities occurring in the time-dependent solutions also plotted in Fig. 5 as a function of time. All velocities are given in the rest frame of the galaxy. The solid line depicts the velocity of the forward shock v_s and the dashed line the reverse shock v_r. The highest gas velocity (filled squares) gives the upstream velocity of the reverse shock v₂. The open triangles plot the post shock velocity v₁ of the reverse shock. The open diamonds correspond to the gas velocity v₀ three diffusive scales in front of the forward shock. In less than about 7 × 10⁷   years or r < 50   kpc, all the velocities become constant and are also given in Table 1.