Large-scale jets from active galactic nuclei as a source of ICM heating: cavities and shocks

TL;DR

This study uses long-term axisymmetric simulations to explore how powerful relativistic jets from active galactic nuclei influence their environment, revealing differences in energy deposition, cavity formation, and heating mechanisms, with implications for galaxy evolution.

Contribution

It provides the first detailed comparison of relativistic and non-relativistic jets' impact on the intracluster medium, highlighting the importance of internal energy and shock heating in cavity formation.

Findings

Light, lepton-dominated jets produce observed X-ray cavities.

Heating is primarily caused by shocks in the environment.

Relativistic and non-relativistic jets show significant differences.

Abstract

The evolution of powerful extragalactic jets is not only interesting by itself, but also for its impact on the evolution of the host galaxy and its surroundings. We have performed long-term axisymmetric numerical simulations of relativistic jets with different powers to study their evolution through an environment with a pressure and density gradient. Our results show key differences in the evolution of jets with different powers in terms of the spatial and temporal scales of energy deposition. According to our results, the observed morphology in X-ray cavities requires that an important fraction of the jet's energetic budget is in the form of internal energy. Thus, light, lepton-dominated jets are favoured. In all cases, heating is mainly produced by shocks. Cavity overpressure is sustained by an important population of thermal particles. Our simulations reproduce the cool-core structure in projected, luminosity-weighted temperature. We have performed an additional simulation of a slow, massive jet and discuss the differences with its relativistic counterparts. Important qualitative and quantitative differences are found between the non-relativistic and the relativistic jets. Our conclusions point towards a dual-mode of AGN kinetic feedback, depending on the jet power.