A faint gamma-ray burst (GRB) captured last Thursday by NASA’s Swift satellite has smashed the record for the earliest, most-distant known object in the universe — with a redshift of about 8.2.
The burst, named GRB 090423 for its discovery date, went off in Leo and was seen to last for 10 seconds. Several teams, including a group using the Gemini-North telescope in Hawaii and a European group using the Very Large Telescope in Chile, followed up the Swift detection by observing the burst’s fading infrared afterglow. Based on how much the afterglow’s light was redshifted (stretched) by cosmic expansion since the era when the burst happened, the group determined that it went off about 630 million years after the Big Bang.
The fading infrared afterglow of GRB 090423 is circled in this infrared image taken with the Gemini North Telescope in Hawaii. The burst is the farthest, earliest cosmic explosion yet seen.