Structured Jets and X-Ray Plateaus in Gamma-Ray Bursts

The X-ray emission of γ-ray bursts (GRBs) is often characterized by an initial steep decay followed by a nearly constant emission phase (so-called "plateau") which can extend up to thousands of seconds. While the steep decay is usually interpreted as the tail of the prompt γ-ray flash, the long-lasting plateau is commonly associated with the emission from the external shock sustained by energy injection from a long-lasting central engine. In this talk I will present the result of a recent study, which propose an alternative interpretation, ascribing both the steep decay and the plateau to high-latitude emission (HLE) from a "structured jet" whose energy and bulk Lorentz factor depend on the angular distance from the jet symmetry axis. I will also show that even when the GRB is observed off-axis this model predicts a bright X-ray transient, which can constitute an interesting target for follow-up observational campaigns of gravitational wave events.

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Meeting ID: 850 4491 0172 
Passcode: 996691