Astronomical searches for axions: observations at the SAO 6-m telescope

The astronomical methods of searching for light Goldstone bosons are discus sed. The basic idea is to use processes of coupling between Goldstone boson s and photons, including (i) the decay of axioms into two photons, and (ii) the transformation of photons into massless axions in the magnetic fields of stars and intergalactic media. The intergalactic light of clusters of ga laxies and the brightness of the night sky owing to axions in the halo of o ur Galaxy are good candidates in which to search for an emission line arisi ng from the radiative decay of axions. The results of observations made by the SAO 6-m telescope in Russia do not provide any evidence for the existen ce of the hadronic axion decay line. The best upper limit on the photon-ari on coupling constant is given by linear polarimetric observations of magnet ic Ap stars.