3D Hydrodynamic Simulations of Relativistic Extragalactic Jets

We describe a new numerical 3D relativistic hydrodynamical code and present the results of three validation tests. A comparison of an axisymmetric jet simulation using the 3D code, with corresponding results from an earlier 2D code, reveal that a) the enforcement of axisymmetry in the 2D case had no significant influence on the global morphology and dynamics; b) although 3D studies typically have lower resolution than those using 2D, limiting their ability to fully capture internal jet structure, such 3D studies can provide a reliable model of global morphology and dynamics. The 3D code has been used to study the deflection and precession of relativistic flows. We find that even quite fast jets (γ ∼ 10) can be significantly influenced by impinging on an oblique density gradient, exhibiting a rotation of the Mach disk in the jet’s head. The flow is bent via a potentially strong, oblique internal shock that arises due to asymmetric perturbation of the flow by its cocoon. In extreme cases this cocoon can form a marginally relativistic flow orthogonal to the jet, leading to large scale dynamics quite unlike that normally associated with astrophysical jets. Exploration of a γ = 5 flow subject to a