Tail Emission of Prompt Gamma-Ray Burst Jets

Yamazaki Ryo

Toma Kenji

Ioka Kunihito

Nakamura Takashi

AIP Conference Proceedings

Tail emission of the prompt gamma-ray burst (GRB) is discussed using a multiple emitting sub-shell (inhomogeneous jet, sub-jets or mini-jets) model, where the whole GRB jet consists of many emitting sub-shells. One may expect that such a jet with angular inhomogeneity should produce spiky tail emission. However, we found that the tail is not spiky but is decaying roughly monotonically. The global decay slope of the tail is not so much affected by the local angular inhomogeneity but affected by the global sub-shell energy distribution. The fact that steepening GRB tail breaks appeared in some events prefers the structured jets. If the angular size of the emit- ting sub-shell is around 0.01-0.02 rad, some bumps or fluctuations appear in the tail emission observed frequently in long GRBs. If the parameter differences of sub-shell properties are large, the tail has frequent changes of the temporal slope observed in a few bursts. Therefore, the multiple emitting sub-shell model has the advantage of explaining the small-scale structure in the observed rapid decay phase.

gamma rays

bursts - gamma rays

theory

Astronomy. Space sciences [ 440 ]

eng

AIP

Copyright (c) 2006 American Institute of Physics

[ISSN] 0094-243X

[DOI] 10.1063/1.2207891

[DOI] http://dx.doi.org/10.1063/1.2207891 isVersionOf