Abstract

Magnetic fields are one of the most fascinating puzzles in the picture of galaxy formation. Recognised important throughout many astrophysical scenarios, they often stand as a major source of uncertainty. In galaxy evolution, one of the major unknowns is which mechanisms generate microGauss magnetic fields in the ISM . Three main alternative pictures stand as possible drivers of their evolution: either magnetic field are of strong primordial origin; amplified by dynamos; or produced by stars or AGN and subsequently fed to the ISM , and possibly further out into the intergalactic medium, polluting the cosmic magnetic field. While each picture appears self-sufficient, current studies struggle to shed light on how these different mechanisms interact or whether one dominates over the others.

I present in this talk our first scientific results using our new algorithm designed to answer these questions by following how magnetic fields from different origins co-evolve. I apply the code to a cosmic zoom-in MHD RAMSES simulation where magnetic fields are sourced simultaneously as an ab-initio primordial field and by magnetised stellar feedback to study the origin of galactic magnetic fields. The two sources are followed separately. I discuss which magnetic source dominates the energy budget in the galaxy and in different parts of its ISM . I review some signatures of these fields and how the stellar-generated field pollutes the primordial magnetic field in the environment.