Strong limits on gut monopole fluxes in magnetic universes

Abstract

We show that any realistic cosmological magnetic field (B ⪝ 10−9 Gauss) may accelerate the heavy GUT magnetic monopoles to high velocities (β ⪝ 10−1) for a very small monopole density (n0 ⪝ 10−32 cm−3) 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 n0 ⪞ 10−32cm−3 the magnetic field and the velocity of the monopole will evolve in damped oscillatory waves with a characteristic time ΔT larger than 6 × 10 6 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.