By Ron Cowen
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.
The telescope started taking pictures just 108 seconds after the burst was detected by the High Energy Transient Explorer (HETE)-2 spacecraft. The ground-based device, the Katzman Automatic Imaging Telescope in Santa Cruz, Calif., traced the afterglow for more than 2.5 hours, until dawn halted observations.