Ten years ago, on Christmas day, satellites detected a gamma-ray burst. The event was not like anything seen before. Was it even a gamma-ray burst? It took three years, several theories, and many observations before astronomers nailed down the event’s origin.
On 4 October 2017, the Swift satellite detected a gamma-ray burst (GRB), an echo of a dying star. The burst was followed by a long-lived emission, called afterglow, which was quickly observed with the Very Large Telescope in Chile. The results were delightful, as the burst offered a rare opportunity to contribute to the study of the Universe’s rise from the Dark age.