Heating the intra-cluster medium by jet-inflated bubbles

TL;DR

This paper investigates how jet-inflated bubbles heat the intra-cluster medium in galaxy clusters, emphasizing the dominant role of mixing over turbulence and shocks, using detailed 3D hydrodynamical simulations.

Contribution

It demonstrates that mixing of hot bubble gas with the ICM is the primary heating mechanism, surpassing turbulence and shock heating, based on comprehensive 3D simulations.

Findings

Mixing accounts for about four times more heating than turbulence.

Turbulent heating plays a smaller role than mixing.

Shock heating is less efficient than mixing.

Abstract

We examine the heating of the intra-cluster medium (ICM) of cooling flow clusters of galaxies by jet-inflated bubbles and conclude that mixing of hot bubble gas with the ICM is more important than turbulent heating and shock heating. We use the PLUTO hydrodynamical code in full 3D to properly account for the inflation of the bubbles and to the multiple vortices induced by the jets and bubbles. The vortices mix some hot shocked jet gas with the ICM. For the parameters used by us the mixing process accounts for about four times as much heating as that by the kinetic energy in the ICM, namely, turbulence and sound waves. We conclude that turbulent heating plays a smaller role than mixing. Heating by shocks is even less efficient.