4 Quotes by Paul Nulsen

We think that the main effect of eruptions like this is to stop stars from forming by preventing hot gas from cooling down.

It might come from a merging galaxy, either gas and stars, or even another black hole falling into an existing black hole. It might also be a large amount of the hot X-ray emitting gas that cooled to low temperature. Either way, it would represent the tail end of galaxy formation.

The interesting issue is, what is the source of the fuel in this case?

The cavities and shock will dissipate, leaving behind very little trace of their existence.