University of Waterloo|Université de Waterloo

Purpose

Hydra A is the most powerful FR I radio source in the nearby Universe. Emanating from the central galaxy in a bright X-ray cluster, its jets have inflated a system of X-ray cavities and a surrounding Mach 1.3 shock front extending several hundred kiloparsecs into the cluster atmosphere. Its proximity (z=0.054) and large angular size requires two pointings to measure the energetics of the active inner jets and a second pointing toward the enormously powerful northern cavity and surrounding shock front. The pointings will reveal the expansion speed and cluster weather due to atmospheric bulk motion on the structure of the X-ray cavities. This measurement addresses the fundamental problem of how jet energy heats cluster atmospheres and prevents catastrophic cooling.