Credit: Martin-Alvarez S., Katz H., Sijacki D., Devriendt J., Slyz A., 2021, MNRAS,504, 2517].

The left panel depicts a mock SDSS view of a Milky Way-like galaxy at rest-frame. The central panel shows instead various physical quantities of interest for the same galaxy. Gas density in cyan, gas temperature in red, and magnetic energy in green. The galaxy in this study is magnetised by both primordial and astrophysical magnetic fields. The magnetic energy is separated into these two origins in the right panel, with primordial magnetic fields shown in green, astrophysical magnetic fields in red. The interaction between both magnetic fields is shown in blue. This image reflects how, when strong enough, primordial magnetic fields survive in galaxies even in the presence of astrophysical magnetisation. More about this result and simulation on Martin-Alvarez et al. (2021).