Speaker
Description
Observations of Faraday rotation and synchrotron emission suggest galaxy clusters harbor large-scale magnetic fields potentially extending to redshift $z=4$. Non-radiative cosmological simulations show slower magnetic growth, while our MHD simulations with galaxy formation physics reveal accelerated amplification. We identify three key phases: (1) High-redshift magnetization of the proto-cluster by the central galaxy through compressive turbulence and feedback-driven outflows; (2) Enrichment of the intracluster medium as merging galaxies transport amplified fields via ram pressure and winds; and (3) Sustained growth at low redshift as accretion and mergers drive small-scale dynamo action. Initially, this amplification occurs in the collisional interstellar medium during proto-cluster assembly and later in the ICM on the magnetic coherence scale, which exceeds the particle mean free path, validating MHD as a framework for studying the cluster dynamo.
