Dark matter and generation of galactic magnetic fields

Understand

A new scenario for creation of galactic magnetic fields is proposed which is operative at the cosmological epoch of the galaxy formation, and which relies on unconventional properties of dark matter.

• Namely, it requires existence of feeble but long range interaction between the dark matter particles and electrons.
• In particular, millicharged dark matter particles or mirror particles with the photon kinetic mixing to the usual photon can be considered.
• We show that in rotating protogalaxies circular electric currents can be generated by the interactions of free electrons with dark matter particles in the halo, while the impact of such interactions on galactic protons is considerably weaker.