Self-organized stable pacemakers near the onset of birhythmicity

General amplitude equations are derived for reaction-diffusion systems near the soft onset of birhythmicity described by a supercritical pitchfork-Hop f bifurcation. Using these equations and applying singular perturbation the ory, we show that stable autonomous pacemakers represent a generic kind of spatiotemporal patterns in such systems. This is verified by numerical simu lations, which also show the existence of breathing and swinging pacemaker solutions. The drift of self-organized pacemakers in media with spatial par ameter gradients is analytically and numerically investigated.