Strong limits on gut monopole fluxes in magnetic universes

We show that any realistic cosmological magnetic field (View the MathML source) may accelerate the heavy GUT magnetic monopoles to high velocities (View the MathML source) for a very small monopole density (View the MathML source) only, corresponding to an almost undetectable flux: F < 10−23 cm−2 s−1. Any larger monopole density will erode the strength of the magnetic field reducing the monopole velocity. For a universe dominated by the mass of the monopoles the flux cannot exceed 10−17 cm−2 s−1. For densities View the MathML source the magnetic field and the velocity of the monopole will evolve in damped oscillatory waves with a characteristic time ΔT larger than 6 × 106 yr. These scales may be reflected in the polarized radiation observable from distant radiosources. The oscillatory behavior of the cosmological field may be responsible for the present random polarization of the cosmological black-body spectrum.