Generation of primordial magnetic fields on linear overdensity scales.

摘要: Magnetic fields appear to be present in all galaxies and galaxy clusters. Recent measurements indicate that a weak magnetic field may even the smooth low density intergalactic medium. One explanation for these observations is seed was generated by some unknown mechanism early life of Universe, later amplified various dynamos nonlinear objects like We show primordial expected Universe on purely linear scales through vorticity induced scale-dependent temperature fluctuations, or equivalently, spatially varying speed sound gas. Residual free electrons left over after recombination tap into this generate via Biermann battery process. Although operates absence any relative velocity between dark matter gas at time recombination, presence such modifies predicted spatial power spectrum field. At redshifts order few tens, we estimate root mean square strength 10(-25)-10(-24) G comoving ~10 kpc. This field, which from perturbations, significantly reionization, further boosted dynamo processes during structure formation.