Constraints on Cosmic Magnetic Monopoles Imposed by the Galactic Magnetic Field

Abstract

Constraints on a hypothetical galactic halo of magnetic monopoles imposed by the galactic magnetic field are discussed. If the field is due to electric currents then a disk-stabilizing galactic monopole halo cannot exist unless the monopole mass ${m}_{M}\ensuremath{\gtrsim}{10}^{21}$ GeV, and then the monopole flux ${F}_{M}\ensuremath{\lesssim}5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{s}}^{\ensuremath{-}1}$. However, if the galactic field is due to monopole charge-density fluctuations then a halo can exist provided ${m}_{M}\ensuremath{\gtrsim}{10}^{17}$ GeV and ${F}_{M}\ensuremath{\lesssim}5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ ${\mathrm{cm}}^{\ensuremath{-}2}$ ${\mathrm{s}}^{\ensuremath{-}1}$.