On the spectrum and polarization of magnetar flare emission
On the spectrum and polarization of magnetar flare emission
复制标题
磁星耀斑发射的光谱和偏振
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
R. Turolla
中科院分区：
文献类型：
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作者：
R. Taverna;R. Turolla
爆发和耀斑是磁星（具有超强磁场（B≈1014-1015 G）的孤立中子星）的独特观测表现。据信，由于磁场不稳定，这些事件发生在注入磁层的热电子-正电子等离子体中，这些等离子体仍然被困在封闭的磁场线内（“被困火球”模型）。我们建立了一个简单的辐射传输模型来模拟稳定捕获火球情况下磁星耀斑的发射。我们假设磁汤姆逊散射是火球介质中不透明的主要来源，忽略了二阶辐射过程的贡献。我们在1-100 keV能量范围内得到的光谱与现有的观测结果基本一致。我们的模型预测的大偏振度（≥80%）应该很容易被新一代的x射线偏振仪测量，如IXPE、XIPE和eXTP，从而可以证实模型的预测。
Bursts and flares are among the distinctive observational manifestations of magnetars, isolated neutron stars endowed with an ultra-strong magnetic field (B ≈ 1014–1015 G). It is believed that these events arise in a hot electron-positron plasma, injected in the magnetosphere, due to a magnetic field instability, which remains trapped within the closed magnetic field lines (the “trapped-fireball” model). We have developed a simple radiative transfer model to simulate magnetar flare emission in the case of a steady trapped fireball. We assume that magnetic Thomson scattering is the dominant source of opacity in the fireball medium, and neglect contributions from second-order radiative processes. The spectra we obtained in the 1–100 keV energy range are in broad agreement with those of available observations. The large degree of polarization (≳ 80%) predicted by our model should be easily measured by new-generation X-ray polarimeters, like IXPE, XIPE and eXTP, allowing one to confirm the model predictions.