Insight into primordial magnetic fields from 21-cm line observation with EDGES experiment

Understand

The recent observation of the 21-cm global absorption signal by EDGES suggests that the intergalactic medium (IGM) gas has been cooler than the cosmic microwave background during $15 \lesssim z \lesssim 20$.

• This result can provide a strong constraint on heating sources for the IGM gas at these redshifts.
• In this paper we study the constraint on the primordial magnetic fields (PMFs) by the EDGES result.
• The PMFs can heat the IGM gas through their energy dissipation due to the magnetohydrodynamic effects.