So far the picture of the interaction between ICM/IGM and the ISM is not very clear. There are many different processes possible that can transport gas from the galaxies to the ICM/IGM: ram-pressure stripping, galactic winds, galaxy-galaxy interaction, jets from active galaxies and maybe even more. It is not known yet, which of the processes is most efficient, what the time variations are and how much it depends on other parameters like e.g. the mass of the cluster/group. The best property to test these different processes is the metallicity. The distribution and the time evolution of the metals are now finally measurable with high accuracy with the X-ray satellites XMM and CHANDRA, so that we will soon get answers on the importance of the different enrichment processes.
We are very grateful to Bernd Aschenbach for making the XMM data of CL0939+4713 available to us. They are part of the TS/MPE guaranteed time.