Time evolution of halo h070 from z ∼ 11 to z = 0 for different magnetically perturbed models. The unperturbed model is shown at the bottom for comparison. In all images are shown the surface density (in comoving units) of the stars (in white), of the gas (in blue), and of the dark matter (in orange). Each box is 20 comoving kpc on a side. In the non-magnetic-field model at high redshifts the gas is dilute and is masked by the orange color of dark matter clumps, which start gathering and then at lower redshifts pull in neutral gas and form stars. However, in the extreme magnetic filed model the gas is more concentrated at high redshifts and a dwarf galaxy is formed very early on.