Magnetar powered GRBs: Explaining the extended emission and X-ray plateau of short GRB light curves

Understand

Extended emission (EE) is a high-energy, early time rebrightening sometimes seen in the light curves of short gamma-ray bursts (GRBs).

• We present the first contiguous fits to the EE tail and the later X-ray plateau, unified within a single model.
• Our central engine is a magnetar surrounded by a fall-back accretion disc, formed by either the merger of two compact objects or the accretion-induced collapse of a white dwarf.
• During the EE phase, material is accelerated to super-Keplarian velocities and ejected from the system by the rapidly rotating ($P \approx 1 - 10$ ms) and very strong ($10^{15}$ G) magnetic field in a process known as magnetic propellering.