Searching for cluster magnetic fields in the cooling flows of 0745-191, A2029, and A4059

We have performed sensitive polarimetric radio observations with the Very Large Array (VLA) of three galaxies: PKS 0745-191, PKS 1508+059, and PKS 2354-350, embedded in x-ray cooling flow clusters. High sensitivity, multifrequency maps of all three, along with spectral index and Faraday rotation measure (RM) maps of PKS 1508+059 and PKS 2354-350 are presented. For PKS 1508+059 and PKS 2354-350 models of the electron density of the intracluster medium (ICM) have been used to set lower limits of 0.1 and 2.7 microG, respectively, on the magnetic field in the ICM based on the observed RMs. In an x-ray selected sample of cooling flow clusters with an associated radio source, 57% (8/14) are found to have absolute RMs in excess of 800 radians/sq m. This sample includes the three sources of this study and all the other high RM sources found to date at zeta less than 0.4. These facts are consistent with the high RM phenomenon being produced by magnetic fields associated with the relatively dense, hot x-ray gas in cooling flow clusters.