Abstract
We review the current understanding of the emission line regions in radio galaxies at redshifts z ~ 1. First, we consider the evolution of the emission line gas properties from the nearby Universe out to z ~ 1. Next, we consider the origin of the ionization and kinematical states of the gas in powerful 3CR radio galaxies at z ~ 1, and in particular show that these evolve very strongly through the lifetime of the radio source due to the profound effect of the passage of the radio source shocks through the interstellar medium of the host galaxy. We show that this dichotomy persists at lower redshifts and also in a lower radio power sample of radio galaxies at the same redshift. We discuss the implications of these results for understanding the nature of the emission line gas and the broader role of jet-cloud interactions.
