Large differential Faraday rotation in the compact steep-spectrum quasar 3C 147 and jet-medium interactions

We present multifrequency radio observations of the prototypical compact steep-spectrum quasar 3C 147, and report enormous differential Faraday rotation between the two extended components on opposite sides of the quasar. This indicates that large amounts of thermal gas are present, and demonstrates directly the existence of asymmetries in the gaseous environment of this source. We suggest a consistent picture for 3C 147, and comment on the evolution of compact steep-spectrum radio sources in general.