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arXiv · astro-ph/0601670

Tail emission from a ring-like jet: its application to shallow decays of early afterglows and to GRB 050709

Y. C. Zou·Z. G. Dai
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Abstract

Similar to the pulsar, the magnetic axis and the spin axis of the gamma-ray burst source may not lie on the same line. This may cause a ring-like jet due to collimation of the precessing magnetic axis. We analyze the tail emission from such a jet, and find that it has a shallow decay phase with temporal index equal to -1/2 if the Lorentz factor of the ejecta is not very high. This phase is consistent with the shallow decay phase of some early X-ray afterglow detected by {\it{swift}}. The ring-like jet has a tail cusp with sharp rising and very sharp decay. This effect can provide an explanation for the re-brightening and sharp decay of the X-ray afterglow of GRB 050709.

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Y. C. Zou, Z. G. Dai. 2006-09-19. Tail emission from a ring-like jet: its application to shallow decays of early afterglows and to GRB 050709. https://doi.org/10.1088/1009-9271%2F6%2F5%2F06

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