Parsec-scale shocks in the kiloparsec-scale jet of Centaurus A
  High angular resolution VLBI observations of Centaurus A have been undertaken
that allow access to a wide field-of-view, encompassing both the well-studied
pc-scale jet and the inner part of the kpc-scale jet. The VLBI observations
have detected compact regions of synchrotron emission in the kpc-scale jet that
coincide with three stationary features identified from previous VLA monitoring
observations. Each of these stationary features is associated with strong
localised X-ray emission. The VLBI results strengthen arguments made by
previous authors suggesting that the stationary features may be the result of
stellar objects or gas clouds traversing the jet flow, intercepting the jet and
causing strong shocks. The VLBI data show that the most strongly shocked
regions in these features are resolved but have extents no larger than a few
pc, reducing the required mass of the typical intercepting object by a factor
of ~10 relative to previous estimates, making explanations based on high mass
loss stars or low density gas clouds more plausible.
