I read an article about a Gamma Ray burst linked to a black hole. How does high gravity fields affect gamma rays?
It's important to be clear that in a gamma ray burst the gamma rays are not generated by the black hole. The process of forming the black hole heats the interior of the star to incredible temperatures, and it's these high temperatures that create the gamma rays.
Any matter that is heated to a high enough temperature will emit gamma rays. The striking thing about the gamma ray bursters is the sheer quantity of energy they emit, and it's this that makes them unique.