Extreme Variability in a Long Duration Gamma-ray Burst Associated with a Kilonova

Understand

The recent discovery of a kilonova from the long duration gamma-ray burst, GRB 211211A, challenges classification schemes based on temporal information alone.

• Gamma-ray properties of GRB 211211A reveal an extreme event, which stands out among both short and long GRBs.
• We find very short variations (few ms) in the lightcurve of GRB 211211A and estimate ~1000 for the Lorentz factor of the outflow.
• We discuss the relevance of the short variations in identifying similar long GRBs resulting from compact mergers.