Galactic-scale evolution of classical and complex radio galaxies. Impact of ambient morphology and jet geometry

TL;DR

This study combines observational analysis and 3D RMHD simulations to explore how jet orientation, environmental resistance, and internal properties influence the morphology and evolution of radio galaxies.

Contribution

It systematically links jet propagation direction and internal jet properties to diverse radio galaxy morphologies through combined observational and simulation approaches.

Findings

Jets along the host's major axis produce X-shaped morphologies.

Intermediate angles yield double-boomerang structures with curved lobes.

Magnetic fields significantly influence the radiative features and irregularities of radio sources.

Abstract

Extragalactic jets exhibit a wide range of propagation orientations relative to the host galaxy's principal axis. This study investigate the spatiotemporal evolution of jets as a function of their propagation direction within their triaxial hosts-introducing varying degrees of environmental hindrance-and as a function of internal jet properties (while maintaining identical jet power)-introducing varying collimation and thrust. Observational data on extended radio sources are re-analyzed to identify key traits arising from variations in jet orientation and intrinsic properties. These findings are then systematically tested using a suite of 3D RMHD simulations. When a jet propagates along host's major axis (path of maximal environmental resistance), it produces an X-shaped morphology with secondary lobe aligns along the minor axis, co-evolving actively alongside the active jet. At intermediate angles to the major axis, the jet morphology transitions into a double-boomerang structure with notably curved lobes. Such lobes are interestingly regenerative through both backflow and jet precession mechanisms, making it difficult to disentangle their origin. Jets propagating along the minor axis (path of minimal resistance) exhibit faster propagation, forming classical double-lobed sources. With increased thrust and improved collimation (keeping jet power constant), these jets advance even more rapidly, potentially evolving into giant radio galaxy candidates. Counterexample sources that deviate from these traits were also modeled. The spatial variation of internal turbulence shows significant fluctuations below 1 kpc, with stronger magnetic fields further suppressing these irregularities. Magnetic field plays a key role in the radiative appearance of these sources, modulating features like missing or one-sided (wing) lobe emission, filamentary structures, and warmspot versus hotspot formation.