  We present here the first analysis of the XMM Newton EPIC-MOS data of the
galaxy group around NGC4839, which lies at a projected distance to the Coma
cluster center of 1.6Mpc. In our analysis, which includes imaging,
spectro-imaging and spectroscopy we find compelling evidence for the sub group
being on its first infall onto the Coma cluster. The complex temperature
structure around NGC 4839 is consistent with simulations of galaxies falling
into a cluster environment. We see indications of a bow shock and of ram
pressure stripping around NGC4839. Furthermore our data reveal a displacement
between NGC4839 and the center of the hot gas in the group of about 300kpc.
With a simple approximation we can explain this displacement by the pressure
force originating from the infall, which acts much stronger on the group gas
than on the galaxies.
