Searching for Axion-like Particles with Active Galactic Nuclei

Abstract

Strong mixing between photons and axion-like particles in the magnetic fields of clusters of galaxies induces a scatter in the observed luminosities of compact sources in the cluster. This is used to construct a new test for axion-like particles; applied to observations of active galactic nuclei it is strongly suggestive of the existence of a light axion-like particle.

Comments: 4 pages, 3 figures. Contribution to the "5th Patras Workshop on Axions, WIMPs and WISPs", Durham 13-17 July 2009