Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

TL;DR

This paper investigates how radial stratification in AGN jets affects their stability, mixing, and overall morphology through 2.5D jet models with different internal structures.

Contribution

It introduces three new AGN jet models with radial structures and analyzes their impact on jet integrity and morphology.

Findings

Radial stratification influences jet stability and mixing.

Different jet structures lead to distinct cocoon morphologies.

Radial profiles affect jet-head propagation dynamics.

Abstract

Current observations have shown that astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angular momentum, the resultant centrifugal forces lead to a radial stratification. Current observations are not able to fully resolve the radial structure, so little is known about its actual profile. We present three AGN jet models in $2.5D$ of which two have been given a radial structure. The first model is a homogeneous jet, the only model that doesn't carry angular momentum; the second model is a spine-sheath jet with an isothermal equation of state; and the third jet model is a (piecewise) isochoric spine-sheath jet, with constant but different densities for jet spine and jet sheath. In this paper, we look at the effects of radial stratification on jet integrity, mixing between the different jet components and global morphology of the jet-head and surrounding cocoon.