Institute for Advanced Study Informal Astrophysics Seminar - NOTE DIFFERENT DAY

Cygnus A is the nearest powerful FR II classical double radio galaxy. We present a detailed study of this galaxy using archival radio and X-ray data. I will first show that the jet precesses, allowing us to determine an upper limit to the velocity of the kpc-scale jet of 0.5c. In the 200 ks Chandra X-ray image we detect emission from a relic counterjet structure. This emission comes from ~10^3 Lorentz factor electrons inverse-Compton scattering of the cosmic microwave background. The relic counterjet feature deflects the current counterjet by ~27 degrees. A relic counterlobe and possibly the relic counter hotspot are detected in the low frequency 151 MHz image. No relic features: jet or lobe, are significantly detected on the jet side, i.e. the side closest to us. This lack of relic emission is explained using light travel time effects. Using the light travel time argument we derive the interval between active jet phases in Cygnus A.