Nonthermal Emission Associated with Strong AGN Outbursts at the Centers of Galaxy Clusters

TL;DR

This paper models particle acceleration and nonthermal emission resulting from strong AGN outbursts in galaxy cluster centers, explaining radio observations and predicting detectable gamma-ray signals.

Contribution

It introduces a simple model linking AGN outbursts to nonthermal emissions, providing estimates consistent with observations and future gamma-ray detectability.

Findings

Radio emission from secondary electrons matches Perseus cluster data.

Strong AGN outbursts >~10^8 years ago can produce observed nonthermal signals.

Gamma-ray emission could be detected with GLAST.

Abstract

Recently, strong AGN outbursts at the centers of galaxy clusters have been found. Using a simple model, we study particle acceleration around a shock excited by an outburst and estimate nonthermal emission from the accelerated particles. We show that emission from secondary electrons is consistent with the radio observations of the minihalo in the Perseus cluster, if there was a strong AGN outburst >~10^8 yrs ago with an energy of ~1.8x10^62 erg. The validity of our model depends on the frequency of the large outbursts. We also estimate gamma-ray emission from the accelerated particles and show that it could be detected with GLAST.