Three-Dimensional Simulations of Bi-Directed Magnetohydrodynamic Jets Interacting with Cluster Environments

TL;DR

This study uses 3D magnetohydrodynamic simulations to analyze how AGN jets transfer energy to galaxy cluster environments, revealing that jets are efficient but do not uniformly heat cluster cores, indicating additional mechanisms are needed.

Contribution

First detailed 3D MHD simulations of AGN jets in realistic, magnetized galaxy clusters examining energy transfer and heating efficiency.

Findings

Jets transfer at least 60% of energy as heat to the ICM.

Energy deposition is localized near jet boundaries, not uniformly distributed.

Intermittency influences energy deposition patterns but does not ensure uniform core heating.

Abstract

We report on a series of three-dimensional magnetohydrodynamic simulations of active galactic nucleus (AGN) jet propagation in realistic models of magnetized galaxy clusters. We are primarily interested in the details of energy transfer between jets and the intracluster medium (ICM) to help clarify what role such flows could have in the reheating of cluster cores. Our simulated jets feature a range of intermittency behaviors, including intermittent jets that periodically switch on and off and one model jet that shuts down completely, naturally creating a relic plume. The ICM into which these jets propagate incorporates tangled magnetic field geometries and density substructure designed to mimic some likely features of real galaxy clusters. We find that our jets are characteristically at least 60% efficient at transferring thermal energy to the ICM. Irreversible heat energy is not uniformly distributed, however, instead residing preferentially in regions very near the jet/cocoon boundaries. While intermittency affects the details of how, when, and where this energy is deposited, all of our models generically fail to heat the cluster cores uniformly. Both the detailed density structure and nominally weak magnetic fields in the ICM play interesting roles in perturbing the flows, particularly when the jets are non-steady. Still, this perturbation is never sufficient to isotropize the jet energy deposition, suggesting that some other ingredient is required for AGN jets to successfully reheat cluster cores.