A gamma-ray burst is a highly luminous flash associated with an explosion in a distant galaxy and producing gamma rays, the most energetic form of electromagnetic radiation, and often followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, and radio).

GRB 030329 was the first burst whose afterglow definitively exhibited characteristics of a supernova, confirming the existence of a relationship between the two phenomena.

[2] GRB 030329 was detected by multiple instruments onboard HETE at 11:37 UTC and lasted approximately 25 seconds.

[7] GRB 030329's proximity to Earth enabled its afterglow to be studied in great detail.

[10] On 10 April 2003, NASA announced that GRB 030329 had provided the definitive link between gamma-ray bursts and supernovae.