Contour plot of activated regulator concentration r_a = r₄ = [R₂S₂] around the time of ignition as a function of time and distance from the center of the colony.

The plot contains the exact solution of the system of equations presented in Eqs (2)–(5) as well as Eq (8), i. e. the system describing total signal molecule concentration. The concentration necessary for ignition ( in the static case) is marked by the red contour. A logarithmic colour-scheme has been chosen due to the large range of values pre- and post-ignition.