A large-scale shock surrounding a powerful radio galaxy?

Abstract

We report Chandra evidence for a 200 kpc scale shock in the cluster surrounding the powerful radio galaxy 3C444. Our 20 ks observation allows us to identify a clear surface brightness drop around the outer edge of the radio galaxy, which is likely to correspond to a spheroidal shock propagating into the intracluster medium. We measure a temperature jump across this drop of a factor 1.7, which corresponds to a Mach number of 1.7. This is likely to be an underestimate due to the need to average over fairly large regions. We also detect clear cavities corresponding to the positions of the radio lobes, which is only the second such detection associated with an FRII radio galaxy. We estimate that the total energy transferred to the environment is >8.2 × 1060erg, corresponding to a jet power >2.9 × 10 45ergs-1. Our results suggest that energy input from FRII radio galaxies is likely to exceed substantially estimates based on cluster cavity scaling relations.