Signatures of magnetar central engines in short GRB lightcurves

Understand

A significant fraction of the Long Gamma-ray Bursts (LGRBs) in the Swift sample have a plateau phase showing evidence of ongoing energy injection.

• We suggest that many Short Gamma-ray Bursts (SGRBs) detected by the Swift satellite also show evidence of energy injection.
• Explaining this observation within the typical SGRB progenitor model is challenging as late time accretion, often used to explain plateaus in LGRBs, is likely to be absent from the SGRB population.
• Alternatively, it is predicted that the remnant of NS-NS mergers may not collapse immediately to a BH (or even collapse at all), forming instead an unstable millisecond pulsar (magnetar) which powers a plateau phase in the X-ray lightcurve.