New results in searching for axions by astronomical methods

Abstract

We discuss the astronomical methods of searching for light Goldstone bosons (axions and arions). The basic idea is to use processes of coupling between axions and photons: a) the axion decay into two photons; b) the transformation process of photons into axions (arions) in the magnetic fields of stars and also of interstellar and intergalactic media; c) the inverse process of transformations of axions (arions) which are generated into cores of stars into X-ray photons. The decaying axions affect upon the diffuse extragalactic background radiation, the brightness of the night sky and especially on the intergalactic light of clusters of galaxies due to generation of the axion radiative decay emission line. The processes (b) and (c) are strongly dependent on polarization state of photon and may produce a noticeable amount of linear polarization.