Cosmic axion background propagation in galaxies

Understand

Many extensions of the Standard Model include axions or axion-like particles (ALPs).

• Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies.
• By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies.
• In particular, we consider a diffuse cosmic ALP background (CAB) analogous to the CMB, whose existence is suggested by string models of inflation.