- the branch of astronomy that deals with the study of celestial objects by means of the gamma rays that come from them.
- the investigation of cosmic gamma rays, such as those from quasars
- The study of astronomical objects by analyzing the gamma rays they emit. Because gamma rays are subject to atmospheric interference that makes them difficult to observe using ground-based telescopes, high-altitude balloons and orbiting observatories are often used to detect them. Most gamma rays in the universe are produced by events such as supernovas and black holes.