Cluster Magnetic Fields from Galactic Outflows

TL;DR

This study uses cosmological magneto-hydrodynamical simulations coupled with galactic wind models to demonstrate that galactic outflows can explain the magnetic fields observed in galaxy clusters, challenging primordial seed field scenarios.

Contribution

It introduces a coupled semi-analytical galactic wind model into cosmological simulations, showing galactic outflows can account for cluster magnetic fields across various parameters.

Findings

Magnetic fields in galaxy clusters are well reproduced by galactic outflow models.

Magnetic pollution in filaments is lower than primordial seed field predictions.

Measuring magnetic fields in low-density environments is more informative about their origin.

Abstract

We performed cosmological, magneto-hydrodynamical simulations to follow the evolution of magnetic fields in galaxy clusters, exploring the possibility that the origin of the magnetic seed fields are galactic outflows during the star-burst phase of galactic evolution. To do this we coupled a semi-analytical model for magnetized galactic winds as suggested by \citet{2006MNRAS.370..319B} to our cosmological simulation. We find that the strength and structure of magnetic fields observed in galaxy clusters are well reproduced for a wide range of model parameters for the magnetized, galactic winds and do only weakly depend on the exact magnetic structure within the assumed galactic outflows. Although the evolution of a primordial magnetic seed field shows no significant differences to that of galaxy clusters fields from previous studies, we find that the magnetic field pollution in the diffuse medium within filaments is below the level predicted by scenarios with pure primordial magnetic seed field. We therefore conclude that magnetized galactic outflows and their subsequent evolution within the intra-cluster medium can fully account for the observed magnetic fields in galaxy clusters. Our findings also suggest that measuring cosmological magnetic fields in low-density environments such as filaments is much more useful than observing cluster magnetic fields to infer their possible origin.