Emission line studies of young radio sources

We demonstrate the efficiency of high quality optical spectroscopic observations of two compact radio sources, PKS 1549-79 and PKS 1345+12, as a probe of the kinematics and physical conditions in the circumnuclear gas in the early stages of radio source evolution. We outline a schematic model for PKS 1345+12 based on the model for PKS 1549-79 proposed by Tadhunter et al. [MNRAS 327 (2001) 227] in which the young radio source is expanding through a dense and dusty enshrouding cocoon, sweeping material out of the circumnuclear regions.