A definitive Herschel study of the most powerful local radio galaxy - Cygnus A

Powerful radio galaxies have played a central role in our understanding of active galaxies over the past five decades. CygnusA, the brightest and most nearby FRII source, has been a Rosetta Stone in this study.It appears to have the outward characteristics of a normal radio galaxybut it.s proximity allows us to identify the more subtle properties ofan obscured quasar. The energy provided by this very active galaxyis sufficient to launch the energetic jets we observe but the transportof the energy to the hotspots is poorly constrained and understood.The growing realisation that AGN directly affect their host galaxythrough a direct feedback mechanism throughout the lifetime of thegalaxy makes it especially important for the most nearby obscured quasar to be observed with the widest possible spectral coverage.We propose to use Herschel to reveal the heating of the central region and the energetics of the hotspots. We request observations of theatomic cooling lines OI, OIII and CII that will allow us to compare theenergetics of the ISM in Cygnus A with other local and more distantgalaxies. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]