The polarization of afterglow emission reveals γ‐ray bursts jet structure
The polarization of afterglow emission reveals γ‐ray bursts jet structure
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DOI：
10.1111/j.1365-2966.2004.08165.x
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发表时间：
2004-01
影响因子：
4.8
通讯作者：
E. Rossi;D. Lazzati;J. Salmonson;G. Ghisellini
中科院分区：
文献类型：
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作者：
E. Rossi;D. Lazzati;J. Salmonson;G. Ghisellini
数值计算了不同喷流光度结构和不同动力学演化下γ射线暴余辉的光变曲线和偏振曲线。我们特别考虑了标准的均匀的“大礼帽”射流和具有幂律机翼的“通用结构射流”。我们还调查了一个可能的，更多的物理变化的“礼帽”模型：“高斯射流”。最后两种喷流类型的偏振曲线在这里显示的第一次与X射线和无线电偏振通量的计算。我们发现，这些配置的总通量的光变曲线是非常相似的，因此只有非常高质量的数据可以让我们确定底层的喷流结构。相反，我们证明，极化曲线是一个强大的手段来解决射流结构，因为预测的行为的极化和它的位置角在射流周围的时间是非常不同的，如果不是相反的。我们的结论是，余辉偏振测量提供了清晰的足迹的任何流出的能量分布（不像总通量的光变曲线）和总通量和偏振通量的联合分析应该揭示的伽玛暴的喷流结构。
We numerically compute light and polarization curves of γ -ray burst (GRB) afterglows for various configurations of the jet luminosity structure and for different dynamical evolutions. We especially consider the standard homogeneous ‘top hat’ jet and the ‘universal structured jet’ with power-law wings. We also investigate a possible, more physical variation of the ‘top hat’ model: the ‘Gaussian jet’. The polarization curves for the last two jet types are shown here for the first time together with the computation of X-ray and radio polarized fluxes. We show that the light curves of the total flux from these configurations are very similar to each other, and therefore only very high quality data could allow us to pin down the underlying jet structure. We demonstrate instead that polarization curves are a powerful means to solve the jet structure, since the predicted behaviour of polarization and its position angle at times around the jet break are very different, if not opposite. We conclude that the afterglow polarization measurements provide clear footprints of any outflow energy distribution (unlike the light curves of the total flux) and the joint analysis of the total and polarized flux should reveal the jet structure of GRBs.