The Connection between Jet Power and Jet Speed in RL AGN

Radio-loud AGN have large-scale jets of relativistic plasma propagating away from the central accreting black hole. Slowed plasma from these jets accumulates into giant radio-emitting lobes on either side of the host galaxy over the lifetime of the jet, resulting in a spatially extended, isotropic synchrotron emission which dominates at low frequencies. The other prominent source of emission at radio frequencies is due to the point source core itself, which can be enhanced by orders of magnitude due to relativistic beaming along the jet axis and typically dominates at higher frequencies. The two sources of emission can be separated through decomposing the low frequency spectrum. Once separated, the extended emission can be used as a proxy for jet power, as it has been shown to correlate with the kinetic power of the jet (Cavagnolo et. al 2010, etc.) and serves as a viable method of estimating it. We have compiled a large catalog of jet proper motions measured by VLBI, to investigate the relation between the apparent speeds and this kinetic jet power. We will present preliminary evidence that the kinetic power of the jet sets an upper bound on the Lorentz factor of the underlying flow within the jet, which is shown through the apparent speeds of plasma being ejected from the core, as measured by VLBI.