Gamma-ray bursts as cool synchrotron sources

Understand

Gamma-ray bursts are the most energetic electromagnetic sources in the Universe.

• Their prompt gamma-ray radiation corresponds to an energy release of 1E42-1E47J.
• Fifty years after their discovery and several dedicated space-based instruments, the physical origin of this emission is still unknown.
• Synchrotron emission has been one of the early contenders but was criticized because spectral fits of empirical models (such as a smoothly-connected broken power law or a cut-off power law) suggest too hard a slope of the low-energy power law, violating the so-called synchrotron line-of-death.