A nearby long gamma-ray burst from a merger of compact objects

Understand

Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions.

• Bursts of long (>2 s) duration are produced by the core-collapse of massive stars, those of short (< 2 s) duration by the merger of two neutron stars (NSs).
• A third class of events with hybrid high-energy properties was identified, but never conclusively linked to a stellar progenitor.
• The lack of bright supernovae rules out typical core-collapse explosions, but their distance scales prevent sensitive searches for direct signatures of a progenitor system.