Hydrodynamics of a perturbation in the jet of 3C111
  We present results on the modelling of the ejection of a superluminal component in the jet of 3C111. We propose that the component is generated by an injection of dense material followed by a decrease in the injection rate of bulk particles in the jet. Our model is supported by 1D relativistic hydrodynamics and emission simulations, and is capable of reproducing the brightness evolution of two features, as revealed by 15 GHz VLBA observations. We show that other scenarios, such as an increase of the Lorentz factor in the material of the perturbation, fails to reproduce the observed evolution of this flare. 
M. Perucho (MPIfR), I. Agudo (IAA), J.L. Gomez (IAA), M. Kadler   (KRO-Uen, NASA Goddard, Usra), E. Ros (MPIfR), Y.Y. Kovale...