Numerical Simulations of Relativistic Jets in Active Galactic Nuclei: The Role of Shocks in the Reheating of the Intracluster Medium

Jets from Active Galactic Nuclei are powerful energy sources that may heat the intracluster medium in galaxy clusters. Their crucial role in the cosmic puzzle, motivated by observations, has been established by a large number of numerical simulations missing the relativistic nature of these jets. We present the first simulations of the very long term evolution of relativistic galactic jets. The runs have been performed in the supercomputer Mare Nostrum, using tipically up to 128 processors and adding up to 200,000 hours of calculation per simulation. Unexpectedly, our results show no buoyant bubbles, but large cocoon regions compatible with the observed X-ray cavities. The heating is more efficient and faster than in previous scenarios, and it is produced by a long lasting shock wave able to survive for several hundreds of Myrs. This result implies a new scenario for the feedback of the most powerful jets.