A first joint M87 campaign in 2008 from radio to TeV gamma-rays
  M87, the central galaxy of the Virgo cluster, is the first radio galaxy
detected in the TeV regime. The structure of its jet, which is not pointing
toward the line of sight, is spatially resolved in X-ray (by Chandra), in
optical and in radio observations. Time correlation between the TeV flux and
emission at other wavelengths provides a unique opportunity to localize the
very high energy gamma-ray emission process occurring in AGN. For 10 years, M87
has been monitored in the TeV band by atmospheric Cherenkov telescopes. In
2008, the three main atmospheric Cherenkov telescope observatories (H.E.S.S.,
MAGIC and VERITAS) coordinated their observations in a joint campaign from
January to May with a total observation time of approx. 120 hours. The campaign
largely overlapped with an intensive VLBA project monitoring the core of M87 at
43 GHz every 5 days. In February, high TeV activities with rapid flares have
been detected. Contemporaneously, M87 was observed with high spatial resolution
instruments in X-rays (Chandra). We discuss the results of the joint
observation campaign in 2008.
