Study of emission mechanism of GRBs probed by the gamma-ray polarization with IKAROS-GAP
Study of emission mechanism of GRBs probed by the gamma-ray polarization with IKAROS-GAP
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DOI：
10.1017/s174392131201366x
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
D. Yonetoku;T. Murakami;T. Sakashita;Y. Morihara;S. Gunji;T. Mihara;K. Toma
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文献类型：
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作者：
D. Yonetoku;T. Murakami;T. Sakashita;Y. Morihara;S. Gunji;T. Mihara;K. Toma
本文报道了利用小型太阳帆演示器IKAROS上的伽玛暴偏振仪（GAP）对GRB 100826 A瞬发γ射线辐射的偏振测量。在瞬发过程中，我们检测到偏振角（PA）的稳定变化，置信水平为99.9%（3.5 σ），平均偏振度（λ）为27 ± 11%，置信水平为99.4%（2.9 σ）。这里引用的误差是针对两个感兴趣的参数在1 σ置信水平下给出的。非轴对称（例如，因此，相对论性喷流内部的磁场和/或亮度的（不规则的）结构需要在可观测的角度尺度~ Γ−1内。我们的观测结果强烈地表明偏振测量是一个强有力的工具来约束伽玛暴的产生机制，需要更多的理论工作来讨论更详细的数据。
Abstract We report a polarization measurement in prompt γ-ray emission of GRB 100826A with the Gamma-Ray Burst Polarimeter (GAP) aboard the small solar power sail demonstrator IKAROS. We detected a firm change of polarization angle (PA) during the prompt emission with 99.9% (3.5 σ) confidence level, and an average polarization degree (Π) of 27 ± 11% with 99.4% (2.9 σ) confidence level. Here the quoted errors are given at 1 σ confidence level for two parameters of interest. Non-axisymmetric (e.g., patchy) structures of the magnetic fields and/or brightness inside the relativistic jet are therefore required within the observable angular scale of ~ Γ−1. Our observation strongly indicates that the polarization measurement is a powerful tool to constrain the GRB production mechanism, and more theoretical works are needed to discuss the data in more details.