Observation of inverse Compton emission from a long $\gamma$-ray burst

Understand

Long-duration gamma-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars.

• They are characterised by an initial phase of bright and highly variable radiation in the keV-MeV band that is likely produced within the jet and lasts from milliseconds to minutes, known as the prompt emission.
• Subsequently, the interaction of the jet with the external medium generates external shock waves, responsible for the afterglow emission, which lasts from days to months, and occurs over a broad energy range, from the radio to the GeV bands.
• The afterglow emission is generally well explained as synchrotron radiation by electrons accelerated at the external shock.