Suppression of Radiative Cooling in Galaxy Cluster Cores by the Combination of AGN Heating and Sloshing

TL;DR

This study uses 3D hydrodynamic simulations to explore how sloshing and AGN heating together influence cooling flows in galaxy cluster cores, revealing complex interactions affecting core heating.

Contribution

It systematically investigates the combined effects of sloshing-driven turbulence and AGN heating on cooling flow suppression in galaxy clusters.

Findings

Sloshing alone can suppress cooling but not fully prevent it.

Longer sloshing wavelengths lead to deeper mixing and greater suppression.

Including AGN heating delays or prevents cooling flows, but sloshing can sometimes reduce feedback efficiency.

Abstract

Recent XRISM observations suggest that gas mixing induced by sloshing contributes to core heating. We systematically investigate the suppression of cooling flows in galaxy cluster cool cores through three-dimensional hydrodynamic simulations that incorporate both sloshing-driven turbulence and active galactic nucleus (AGN) heating. The AGN heating is modeled as thermal energy input that mimics cosmic-ray heating. Sloshing is represented by simple waves with amplitudes \alpha = 0, 0.15, and 0.3 times the sound speed and wavelengths \lambda = 200, 1000, and 2000 kpc. We evolve each model from an isothermal initial condition to t = 8 Gyr. Without AGN heating, sloshing suppresses cooling, but it cannot stop it completely unless the core is fully disrupted. Longer wavelengths promote deeper mixing and greater suppression. Sloshing can cause cooler gas to move more quickly than hotter gas. This phenomenon has been observed in a few clusters by XRISM. When AGN heating is included, the dense central gas is heated efficiently, substantially delaying or preventing the onset of a cooling flow. However, for intermediate wave lengths, sloshing can displace the densest gas away from the AGN heating zone, reducing the feedback effect and paradoxically enhancing net cooling relative to the wave-free case. These results highlight a non-trivial coupling between sloshing and AGN feedback, with implications for interpreting XRISM velocity and temperature maps of cool-core clusters.