The extreme flare in III Zw 2: Evolution of a radio jet in a Seyfert   galaxy
  A very detailed monitoring of a radio flare in the Seyfert I galaxy III Zw 2 with the VLA and the VLBA is presented. The relative astrometry in the VLBA observations was precise on a level of a few microarcseconds. Spectral and spatial evolution of the source are closely linked and these observations allowed us to study in great detail a textbook example of a synchrotron self-absorbed jet. We observe a phase where the jet gets frustrated, without expansion and no spectral evolution. Then the jet breaks free and starts to expand with apparent superluminal motion. This expansion is accompanied by a strong spectral evolution. The results are a good confirmation of synchrotron theory and equipartition for jets. 
A. Brunthaler (1,2), H. Falcke (3,4), G.C. Bower (5), M.F. Aller (6),   H.D. Aller (6), H. Teraesranta (7) ((1) Max-Plank In...