The Jet in M87 from e-EVN Observations
  One of the most intriguing open questions of today's astrophysics is the one
concerning the location and the mechanisms for the production of MeV, GeV, and
TeV gamma-rays in AGN jets. M87 is a privileged laboratory for a detailed study
of the properties of jets, owing to its proximity, its massive black hole, and
its conspicuous emission at radio wavelengths and above. We started on November
2009 a monitoring program with the e-EVN at 5 GHz, during which two episodes of
activity at energy E > 100 GeV have occured. We present here results of these
multi-epoch observations. The inner jet and HST-1 are both detected and
resolved in our datasets. One of these observations was obtained at the same
day of the first high energy flare. A clear change in the proper motion
velocity of HST-1 is present at the epoch ~2005.5. In the time range 2003 --
2005.5 the apparent velocity is subluminal, and superluminal (~ 2.7c) after
2005.5.
