NGC-1275 AND THE PERSEUS CLUSTER - THE FORMATION OF OPTICAL FILAMENTS IN COOLING GAS IN X-RAY-CLUSTERS

We discuss the role of angular momentum in radiatively cooling gas flows within rich clusters of galaxies, and consider the growth rate of perturbations owing to thermal instability in such flows. The formation of the low-velocity optical filamentation surrounding NGC 1275 in the Perseus cluster is considered in the context of the model, and excitation mechanisms are discussed. We show that mass flow rates through the core of the cluster and the mass-to-light ratio for NGC 1275 can be derived from the optical observations and that the procedure is consistent with the interpretation of the X-ray observations. Similar systems of optical filamentation should be a general signature of clusters where radiative cooling of the intercluster gas is occurring, and may yield detailed information on the gas and galaxies within such clusters. © 1980 Royal Astronomical Society. Provided by the NASA Astrophysics Data System.