Ros et all,,
Mechanically speaking, I suspect some of the gamma ray bursts are significant in the deaths and births of galaxies.
What makes you think this?
When a galaxy has lost enough of its orbital (inertial-kinetic) energies all its mass will be concentrated in a "black hole".
As far as I know, Galaxies do not lose orbital kinetic energy any more than our solar system does. Galaxies do collide however, and when they do, they are disrupted sufficiently to send more material into the central super massive black holes which are the foundation of most galaxies. But they do not lose kinetic energy without interacting with something else, and for the most part, there is nothing else to interact with.
Since most mechanical devices can only absorb a fixed amount of energies before changing (form-shape-state) in effect; blowing up. I suspect that this is whats happening.
This is unlikely given what we know about Black Holes.
Black Holes are not like normal mechanical devices, or physical phenomena. They do not overload and burst (based on the math of the standard models, which have been largly confirmed). They just keep getting more and more massive as they consume things.