Question

The reason for this correlation is not fully understood, but most astronomers take it to mean that the evolution of normal and active galaxies must be very closely connected. By observing galaxies at different distances and corresponding look-back times, astronomers have concluded that supermassive black holes were created as galaxies merged during (or just before) the quasar epoch 10-12 billion years ago. How did galactic mergers contribute to the development of supermassive black holes?

Answer 1

Answer: The hierarchical formation model suggests that galaxies may have been formed  by subsequent mergers of smaller galaxies and that today each galaxy houses at least  a supermassive black hole.

Explanation: During a fusion of galaxies, the stars that composes it suffer the tidal force, intensifying your action as the galaxies approaching. When two galaxies merges themselves, the astronomers believes that they loss a huge part of their mass, forming the supremassive black hole, that stays in the middle of the galaxie.

The supermassive black holes are originated from the evolution of high mass stars. They were formed by huge clouds of gas or clusters of millions of stars that collapsed on their own gravity when the universe was still much younger and denser.