Though they happen several times a day, it was not until 1999 that ROTS-1 at Los Alamos was able to make a visible-light observation of one.  
Though they happen several times a day, it was not until 1999 that ROTS-1 at Los Alamos was able to make a visible-light observation of one.  After the initial event, an x-ray afterglow often persists for several days. They were first observed by US Vela nuclear test detection satellites in the 1960's, and since then black holes, colliding neutron stars, and ordinary supernovae have all been hypothesized as their source.  FTP, name these cosmic events marked by a sudden, intense increase in high-energy radiation, and often referred to as GRBs [G-R-B-ees].
Though they happen several times a day, it was not until 1999 that ROTS-1 at Los Alamos was able to make a visible-light observation of one.  
gamma-ray burster (accept early buzz of GRB)