The blue dot in the centre of this image (shown by the arrow) is the optical light signature of GRB011121, the gamma-ray burst detected by Ulysses, Mars Odyssey and BeppoSAX on 21 November 2001. The gamma-ray burst briefly appeared brighter than the rest of the Universe in gamma rays, before rapidly fading away.

This optical image, taken with the National Science Foundation's Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile during the morning of 23 November 2001, shows the optical transient a day and a half after the initial burst. The transient had faded in brightness from its peak by more than a factor of 100 in that period of time. The reddish dot adjoining the gamma-ray burst, at its lower left, is probably the core of the galaxy in which the gamma-ray burst occurred.

photo: M.Brown,R.Schommer,K.Olsen, B.Jannuzi,A.Dey(NOAO),A.Fruchter,J.Rhoads(STSci) AURA/NSF