Active galactic nuclei jets simulated with smoothed particle hydrodynamics

Simulations of active galactic nuclei (AGN) jets have thus far been performed almost exclusively using grid-based codes. We present the first results from hydrodynamical tests of AGN jets, and their interaction with the intracluster medium (ICM), using smoothed particle hydrodynamics as implemented in the SWIFT code. We launch these jets into a constant-density ICM, as well as ones with a power-law density profile. We also vary the jet power, velocity, opening angle, and numerical resolution. In all cases we find broad agreement between our jets and theoretical predictions for the lengths of the jets and the lobes they inflate, as well as the radii of the lobes. The jets first evolve ballistically, and then transition to a self-similar phase, during which the lobes expand in a self-similar f ashion (k eeping a constant shape). In this phase the kinetic and thermal energies in the lobes and in the shocked ICM are constant fractions of the total injected energy. In our standard simulation, two thirds of the initially injected energy is transferred to the ICM by the time the jets are turned off, mainly through a bow shock. Of that, 70% is in kinetic form, indicating that the bow shock does not fully and efficiently thermalize while the jet is active. At resolutions typical of large cosmological simulations (m(gas) asymptotic to 10(7) M-(sic)), the shape of the lobes is close to self-similar predictions to an accuracy of 15%. This indicates that the basic physics of jet-inflated lobes can be correctly simulated even at such resolutions (asymptotic to 500 particles per jet).

Automated summary

This study presents the first hydrodynamical tests of active galactic nuclei (AGN) jets using smoothed particle hydrodynamics. The simulation results show agreement with theoretical predictions for the lengths, radii, and shapes of the jet-inflated lobes in the intracluster medium (ICM). The jets transition from a ballistic phase to a self-similar phase, and a significant amount of the injected energy is transferred to the ICM in the form of kinetic energy.