Optical, Ultraviolet, and Infrared Observations of Cooling Flows in Rich Clusters

Abstract

Many rich clusters are now known to possess centrally located optically emitting gas systems, which accompany large (~ l00M _⊙/year) inflows of cooling cluster gas. We report on recent results of optical, UV, and IR studies on cooling flow clusters. The work centers on three topics: (1) Spectroscopic studies of the velocity structure of the line-emitting gas systems have been used to probe the dynamics of the central cluster regions. (2) Filter imaging studies of cluster emission line systems have yielded line luminosities and characteristic angular scales. We discuss the implications of both data sets for the cosmological evolution of galaxies and gas in clusters. (3) Finally, we report the results of combining our optical survey with similar surveys undertaken by us using ultraviolet and infrared satellite data. Carefully flux-calibrated data from this multi-wavelength data base have been used to show that a small but significant component of dust extinction is associated with the environment of these clusters. The measured IR flux and the extinction values are used to suggest that substantial recent injection of material into the cluster atmospheres has taken place.