Fields and Filaments in the Core of the Centaurus Cluster

TL;DR

This study investigates the magnetic fields and gas structures in the core of the Centaurus cluster using high-resolution imaging of Faraday Rotation, revealing complex interactions between magnetic fields, hot gas, and optical filaments.

Contribution

The paper provides detailed measurements of magnetic field strengths and their organization in the cluster core, linking magnetic structures with multi-wavelength gas emissions and dynamics.

Findings

Magnetic fields of ~25 microG organized on ~1 kpc scales.

Hot gas at 5 million K with density ~0.1 cm^-3 correlates with RM and X-ray features.

Magnetic pressure is insufficient to stabilize optical filaments.

Abstract

We present high resolution images of the Faraday Rotation Measure (RM) structure of the radio galaxy PKS 1246-410, at the center of the Centaurus cluster. Comparison with Halpha-line and soft X-ray emission reveals a correspondence between the line-emitting gas, the soft X-ray emitting gas, regions with an excess in the RM images, and signs of depolarization. Magnetic field strengths of 25 microG, organized on scales of ~1 kpc, and intermixed with gas at a temperature of 5 x 10^6 K with a density of ~0.1 cm^-3 can reproduce the observed RM excess, the depolarization, and the observed X-ray surface brightness. This hot gas may be in pressure equilibrium with the optical line-emitting gas, but the magnetic field strength of 25 microG associated with the hot gas provides only 10% of the thermal pressure and is therefore insufficient to account for the stability of the line-emitting filaments.