Emission-line properties of 3CR radio galaxies .2. Velocity fields in the extended emission lines

We analyze long-slit spectra of 30 3CR and 1 Jy class radio galaxies to derive the velocity fields in the extended emission-line regions. Amplitudes of 1000 km s(-1) or more are found in several high-redshift objects. Complex motions are seen in the emission-line nebulae of several galaxies, while others have kinematics consistent with simple rotation. The velocity widths of the extranuclear gas are often large, particularly in regions of high shearing motions. While a wide range of amplitude and structure is seen in the velocity curves, a few trends are apparent both within this sample and when comparing this sample to low-redshift radio galaxies. The amplitudes at high redshift are on average higher than those seen in the local samples. Our survey also reveals a number of systems with fully detached emission-line regions with velocity differences of several hundred km s(-1). At present it is unclear if these differences reflect a change with cosmic time or if they reflect the luminosity bias inherent in the 3CR and other flux-limited samples. These issues will be examined when we compare our results with similar data on low-redshift radio galaxies in Paper III.