Contour of T − T₀ at a) t = 1000τ_A, b) t = 10   000τ_A and c) t = 100   000τ_A. Dashed white line denotes x = 35. d) Plots (diamonds) the location of the maximum of T − T₀ over 2000τ_A ≤ t ≤ 100   000τ_A. Also plotted (single star) is the location at t = 1000τ_A. In subfigures a) − c), each colour bar represents magnitude, whereas in (d) the corresponding colour bar donotes time.