GRB 090423
GRB 090423 was a gamma-ray burst (GRB) detected by the Swift Gamma-Ray Burst Mission on April 23, 2009, at 07:55:19 UTC whose afterglow was detected in the infrared and enabled astronomers to determine that its redshift is z = 8.2, making it one of the most distant objects detected at that time with a spectroscopic redshift (GN-z11, discovered in 2016, has a redshift of 11). A gamma-ray burst is an extremely luminous event flash of gamma rays that occurs as the result of an explosion, and is thought to be associated with the formation of a black hole.