Intergalactic magnetic fields are the weakest magnetic fields present in the Universe. They might be relics from the Early Universe produced at the epochs of cosmological phase transitions. Such fields might have served as initial “seed” fields for the action of galactic dynamos amplifying the fields to the microGauss-scale values observed in today’s galaxies. Otherwise, intergalactic magnetic fields might be spread into the intergalactic medium at the late stages of cosmological evolution by the galactic winds. I will review recent progress on the measurements of intergalactic magnetic fields using the techniques of gamma-ray astronomy and on the theoretical understanding of the origin of these fields.

ISDC Geneva