A simulation study of ultra-relativistic jets: The morphology and properties of radio galaxies

Abstract

Through three-dimensional relativistic hydrodynamics (RHD) simulations, we study the properties of ultrarelativistic jets on kpc scales, including the morphology as well as the nonlinear dynamics generated by the jets. To that end, we have developed a new high-order, shock-capturing, RHD code, equipped with the WENO-Z scheme and a realistic equation of state (Seo et al. 2020). Exploring a set of models with various parameters, we confirm that the well-known Fanaroff-Riley dichotomy is primarily determined by the jet power, whereas the morphology of simulated jets also depends on the secondary parameters such as the momentum injection rate and the ratio of the jet to background pressures. Utilizing high-resolution capabilities of the newly developed code, we quantify the distributions and statistics of shocks, velocity shear, and vorticity in different parts of the jet-induced flows. We find that shocks formed in the jet plasma and backflows are the most effective in dissipating the jet energy, while the shear appears largest across the jet and backflows.