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arXiv · 1407.0588

Revisiting the Emission from Relativistic Blast Waves in a Density-Jump Medium

J. J. Geng·X. F. Wu·Liang Li·Y. F. Huang·Z. G. Dai
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Abstract

Re-brightening bumps are frequently observed in gamma-ray burst (GRB) afterglows. Many scenarios have been proposed to interpret the origin of these bumps, of which a blast wave encountering a density-jump in the circumburst environment has been questioned by recent works. We develop a set of differential equations to calculate the relativistic outflow encountering the density-jump by extending the work of Huang et al. (1999). This approach is a semi-analytic method and is very convenient. Our results show that late high-amplitude bumps can not be produced under common conditions, only short plateau may emerge even when the encounter occurs at early time ($< 10^4$ s). In general, our results disfavor the density-jump origin for those observed bumps, which is consistent with the conclusion drawn from full hydrodynamics studies. The bumps thus should be due to other scenarios.

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J. J. Geng, X. F. Wu, Liang Li, Y. F. Huang, Z. G. Dai. 2014-07-02. Revisiting the Emission from Relativistic Blast Waves in a Density-Jump Medium. https://doi.org/10.1088/0004-637x/792/1/31

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