Axion production from primordial magnetic fields

Understand

Production of axionlike particles (ALPs) by primordial magnetic fields may have significant impacts on cosmology.

• We discuss the production of ALPs in the presence of the primordial magnetic fields.
• We find a region of the ALP mass and photon coupling which realizes the observed properties of the dark matter with appropriate initial conditions for the magnetic fields.
• This region may be interesting in light of recent indications for the 3.5 keV lines from galaxy clusters.