The origin of ripples in cool cores of galaxy clusters: Heating by magnetohydrodynamic waves?

We consider MHD waves as a heating source of cool cores of galaxy clusters. In particular, we focus on transverse waves (Alfven waves), because they can propagate a longer distance than longitudinal waves ( sound waves). Using MHD simulations, we found that the transverse waves can stably heat a cool core if the wave period is large enough ( greater than or similar to 10(8) yr). Moreover, the longitudinal waves that are created as a by-product of the nonlinear evolution of the transverse waves could be observed as the ripples found in cool cores.