Relativistic hydrodynamic simulations show FRI jets heat ICM with 80% efficiency via weak shocks

The simulations track continuous jet activity with radiative cooling in cosmologically extracted cluster cores. Weak bow shocks dominate energy transfer rather than strong shocks or direct mixing, converting kinetic power into thermal energy while bremsstrahlung cooling tempers the expanding shells. This directly addresses the cooling-flow problem by showing low-power jets can offset radiative losses without requiring extreme powers. Prior analytic models overestimated shock strengths; these runs reveal rapid deceleration and environmental coupling regulate deposition more efficiently than assumed. The work connects to observed X-ray cavities and ripples in clusters like Perseus, where similar weak features imply widespread AGN regulation of star formation. Next steps include coupling these hydro results to cosmic-ray and magnetic-field modules to test whether non-thermal pressure further alters shock propagation and long-term thermal balance.