Gamma-ray burst leaves ephemeral afterglow

A ground-based telescope on automatic pilot has recorded the visible-light afterglow of a gamma-ray burst less than 2 minutes after the eruption. One of the most energetic flashes of radiation known in the universe, gamma-ray bursts seem to be generated when a massive star collapses on itself and becomes a black hole or when a black hole merges with a superdense neutron star.