GRB 990510

The object of study is the remnant of a mysterious cosmic explosion far out in space, first detected as a gigantic outburst of gamma rays on May 10. Gamma-Ray Bursters (GRBs) are brief flashes of very energetic radiation — they represent by far the most powerful type of explosion known in the Universe and their afterglow in optical light can be 10 million times brighter than the brightest supernovae. The May 10 event ranks among the brightest one hundred of the over 2500 GRB's detected in the last decade. This is a visual image of the sky field around GRB 990510 (here denoted "OT"), as obtained with the VLT ANTU telescope and FORS1 on May 18 UT during a 20 min exposure in 0.9 arcsec seeing conditions. The reproduction is in false colours to better show differences in intensity. North is up and east is left.