The impact of flickering variability and magnetization on the dynamics, stability, and morphology of radio-loud AGN jets

The physics governing the morphology of radio-loud active galactic nucleus (AGN) jets is not fully understood. We investigate how magnetization, flickering jet power and the interplay between them affects the morphology of radio galaxies. We present a grid of relativistic magnetohydrodynamic simulations using the pluto code covering constant and variable jets with two levels of magnetization. We find that the constant high-magnetization jets can lead to highly asymmetrical cocoon morphologies, while the variable high-magnetization jet can exhibit a broken morphology, caused by a discontinuous jet beam. Our work highlights the importance of magnetization and variability on the stability and resulting morphology of radio-loud AGN jets, suggesting both are significant factors in addition to jet power or environment. Furthermore, we show that the interaction between magnetization and variability can lead to the development of localized kink instabilities along the jet beam. Finally, we discuss the effects of hydrodynamic mixing in low-magnetization jets and the role of viewing-angle dependence in comparisons between our simulations and observed sources. To facilitate this comparison we present a library of simulated radio images at different times in the simulations and from various viewing angles, which highlight a diverse set of complex morphologies.