Gamma‐ray burst systematics

The systematics of gamma‐ray bursts are considered. Categorization within this class of events appears reasonable based upon both temporal and spectral features. The gamma ray bursts can be categorized as bursts like the 1979 March 5 event, bursts like the 20 minute transient observed by Jacobsen, and classical (that is, normal) bursts. Further, the classical bursts can be subdivided into bursts which are very brief, bursts with a doublet or quasi‐periodic time structure, or bursts which are long and irregular. There appears to be a correlation between the occurrence of emission lines and the doublet or quasi‐periodic class and also between the occurrence of absorption lines and the long and irregular class.