"T.Brown": We conclude that the observed decrease of gas content in the Galaxy group and cluster environments cannot be reproduced by starvation of the gas supply alone and invoke fast acting processes such as ram-pressure stripping of cold gas to explain this."( see: Galaxy Murder Mystery: https://www.sciencedaily.com/releases/2017/01/170116160620.htm )
Quantum-FFF theory answer:
Ram Pressure Stripping (Galaxy killing) is supposed to be originated, by the increasing electric/ spacetime complexity inside the network of external electric dark matter black holes (or: GABHs: Galaxy Anchor Black Holes) around multiple merged cluster galaxies.
The complexity is supposed to kill the formation of dual black hole based linear electric Herbig Haro (HH) systems!
HH systems are supposed to form a central star forming pressure cooker effect.
Galaxy cluster killing seem to be a support for a cyclic universe and the start of the Big Crunch!