GALAXY EVOLUTION IN THE VIRGO CLUSTER
B. Vollmer

The environement plays a key role for the evolution
of galaxies residing in galaxy clusters.
A galaxy entering a cluster can have three kinds of
(i) an interaction with the gravitational potential of the cluster,
(ii) an interaction with another galaxy,
(iii) ram pressure stripping due to the galaxy's rapid motion
through the hot intracluster medium.
Since Virgo is the nearest cluster in the northern hemisphere,
it represents an ideal place to investigate these interactions in detail.
We have studied 8 individual Virgo cluster galaxies that experienced
or experience interaction (ii), (iii) or a mixture of both.
Detailed comparisons between simulated and observed gas distributions
and velocity fields allow us to identify the kind of
interaction that the galaxy underwent and to determine the interaction
parameters. In this way a temporal sequence of ram pressure stripping in
the Virgo cluster could be established. Especially the polarized radio
continuum emission of Virgo spiral galaxies is a useful tool to
make interaction diagnostics. We are now at the point where we
can start to study the gas physics of these interactions
(evaporation, phase mixing, change of phase, star formation).