  The hot X-ray emitting plasma in galaxy clusters is predicted to have
turbulent motions which can contribute around ten percent of the cluster's
central energy density. We report deep Chandra X-ray Observatory observations
of the Coma cluster core, showing the presence of quasi-linear high-density
arms spanning 150 kpc, consisting of low-entropy material likely stripped from
merging subclusters. Two appear to be connected with a subgroup of galaxies at
650 kpc radius that is merging into the cluster, implying coherence over
several hundred Myr. Such long lifetime implies that strong isotropic
turbulence and conduction are suppressed in the core, despite the unrelaxed
state of the cluster. Magnetic fields are presumably responsible. The
structures seen in Coma present insight into the past Gyr of subcluster merger
activity.
