GAMMA-RAY POLARIZATION INDUCED BY COLD ELECTRONS VIA COMPTON PROCESSES
GAMMA-RAY POLARIZATION INDUCED BY COLD ELECTRONS VIA COMPTON PROCESSES
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DOI：
10.1088/0004-637x/769/1/70
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发表时间：
2013-01
期刊：
影响因子：
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通讯作者：
Z. Chang;Yunguo Jiang;Hai-Nan Lin
中科院分区：
文献类型：
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作者：
Z. Chang;Yunguo Jiang;Hai-Nan Lin
偏振测量是探测伽马射线暴（GRB）瞬发发射机制的重要工具。同步加速器光子可以通过康普顿散射（CS）过程被流出中的冷电子散射。观察到的偏振取决于光子能量和视角。在典型的体洛伦兹因子 Г∼200 的情况下，能量 E > 10 MeV 的光子往往比能量 E < 1 MeV 的光子具有更小的偏振。在右视角，即 θ ∼ Г−1 处，偏振达到最大值，偏振角度相对于初始偏振方向改变 90°。因此，同步辐射加CS模型可以自然地解释GRB 100826A中偏振角90°的变化。
The polarization measurement is an important tool to probe the prompt emission mechanism in gamma-ray bursts (GRBs). The synchrotron photons can be scattered by cold electrons in the outflow via Compton scattering (CS) processes. The observed polarization depends on both the photon energy and the viewing angle. With the typical bulk Lorentz factor Γ ∼ 200, photons with energy E > 10 MeV tend to have smaller polarization than photons with energy E < 1 MeV. At the right viewing angle, i.e., θ ∼ Γ−1, the polarization achieves its maximal value, and the polarization angle changes 90° relative to the initial polarization direction. Thus, the synchrotron radiation plus CS model can naturally explain the 90° change of the polarization angle in GRB 100826A.