Observations of magnetic fields in regular and irregular clusters
  The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. The most detailed evidence for the presence of cluster magnetic fields comes from radio observations. Magnetic fields can be investigated through the synchrotron emission of cluster-wide diffuse sources and from studies of the rotation measure of polarized radio galaxies. I will review efforts to measure magnetic field strengths and power spectra and the main issues that have led to our knowledge on magnetic fields in regular and irregular clusters of galaxies. 
Federica Govoni (1,2) ((1)INAF - Osservatorio Astronomico di Cagliari,   (2) INAF - Istituto di Radioastronomia)