At left is a prior sky survey image of the region which astonishingly shows a discernible smudge near the same position, likely the burster's host galaxy. Still, believed to be the most powerful explosions in the Universe, the source of the incredible energy of gamma-ray bursts remains a mystery. Reported redshift measurements now suggest that the burst is instead a very distant one. The galaxy in the survey image may not be the gamma-ray burst host but a foreground galaxy which by chance lies along the line of sight from Earth to the burster. If so, this raises the intriguing possibility that the foreground galaxy's gravity may act like a lens and produce multiple images of the gamma-ray burst.
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