Very high frequency (and therefore very high energy) electromagnetic radiation emitted as a consequence of radioactivity.

attributive form of gamma ray

plural of gamma ray

(astronomy) A flash of gamma rays that seem to originate from a random point in the sky; their most likely sources are believed to be supernova explosions of a very massive stars and mergers of neutron stars.

(astronomy) An observational branch of astronomy, which deals with the study of gamma-ray emission from celestial objects.

plural of gamma-ray burst