Long-term FRII jet evolution in dense environments

TL;DR

This study uses long-term 3D simulations to explore how dense environments influence the evolution and morphology of relativistic FRII jets, revealing effects on jet stability, structure, and interaction with surrounding media.

Contribution

It provides new insights into the impact of dense media on jet dynamics, including reduced perturbation effects and earlier onset of instabilities, extending previous lower-density studies.

Findings

Dense media reduce jet perturbation effects.

Jet morphology becomes less elongated with prominent lobes.

Shock heating remains highly efficient in dense environments.

Abstract

We present long-term numerical three-dimensional simulations of a relativistic outflow propagating through a galactic ambient medium and environment, up to distances $\sim 100$~kpc. Our aim is to study the role of dense media in the global dynamics of the radio source. We use a relativistic gas equation of state, and a basic description of thermal cooling terms. In previous work, we showed that a linear perturbation could enhance the jet propagation during the early phases of evolution, by introducing obliquity to the jet reverse shock. Here, we show that this effect is reduced in denser media. We find that the dentist-drill effect acts earlier, due to slower jet propagation and an increased growth of the helical instability. The global morphology of the jet is less elongated, with more prominent lobes. The fundamental physical parameters of the jet generated structure derived from our simulations fall within the estimated values derived for FRII jets in the 3C sample. In agreement with previous axisymmetric and three dimensional simulations in lower density media, we conclude that shock heating of the interstellar and intergalactic media is very efficient in the case of powerful, relativistic jets.