MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION
MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION
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DOI：
10.1088/2041-8205/758/1/l1
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
D. Yonetoku;T. Murakami;S. Gunji;T. Mihara;K. Toma;Y. Morihara;Takuya Takahashi;Y. Wakashima
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文献类型：
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作者：
D. Yonetoku;T. Murakami;S. Gunji;T. Mihara;K. Toma;Y. Morihara;Takuya Takahashi;Y. Wakashima
我们报道了在IKAROS太阳帆任务中用伽马射线暴偏振仪(GAP)观测到的两个伽马射线暴GRB 110301A和GRB 110721A的偏振测量。我们从每个猝发中检测到线偏振信号，偏振度Π=70±22%，统计意义为3.7GRB110301A，Π=84+16−28%，3.3GRB110721A的置信度为3.3σ。我们没有发现偏振角有任何明显的变化。与GRB 100826A相比，这两次事件持续时间更短，亮度更暗，显示出偏振角的显著变化，Yonetoku等人报道了这两次事件。同步辐射模型可以与三个伽玛暴的观测数据相一致，而光球准热辐射模型则不被看好。我们认为发射区的磁场结构是从中心引擎平流而来的全局有序场。
We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of Π = 70 ± 22% with statistical significance of 3.7σ for GRB 110301A, and Π = 84+16− 28% with 3.3σ confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.