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arXiv 2304.04570astro-ph.HE
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各向异性扩散下磁场关联长度对伽马射线脉冲星晕形态的影响

Effect of magnetic field correlation length on the gamma-ray pulsar halo morphology under anisotropic diffusion

Kun Fang, Hong-Bo Hu, Xiao-Jun Bi, En-Sheng Chen

AI总结:

本文研究了各向异性扩散下磁场关联长度对伽马射线脉冲星晕形态的影响,通过半解析方法求解传播方程,发现有限关联长度场景下的晕形态与无限关联长度场景存在差异,可由当前实验验证。

摘要:

各向异性扩散是Geminga脉冲星晕形态的潜在解释之一。它通过几何效应解释观测到的慢扩散现象,假设Geminga周围的平均磁场方向与指向其的视线方向紧密对齐。然而,该方向不应延伸超过湍流磁场的关联长度$L_c$,该长度可能为$100$ pc或更短。我们首先重新审视$L_c=\infty$场景,并表明该场景预测的晕不对称性主要由Geminga周围长度为$100$ pc的“核心”区域之外的电子贡献。然后,考虑到核心区域之外磁场方向的变化,我们以一个磁场配置为例,研究可能的晕形态。与$L_c=\infty$场景相比,预测的形态具有一些不同特征。当前的实验可能已经能够测试这些特征。此外,我们使用半解析方法求解各向异性传播方程,与数值方法相比,这提供了显著的便利。

英文摘要:

Anisotropic diffusion is one of the potential interpretations for the morphology of the Geminga pulsar halo. It interprets the observed slow-diffusion phenomenon through a geometric effect, assuming the mean magnetic field direction around Geminga is closely aligned with the line of sight toward it. However, this direction should not extend further than the correlation length of the turbulent magnetic field $L_c$, which could be $100$ pc or less. We first revisit the $L_c=\infty$ scenario and show that the halo asymmetry predicted by this scenario is mainly contributed by the electrons located beyond the ``core" section around Geminga, which has a length of $100$ pc. Then, considering the directional variation of the magnetic field beyond the core section, we take one magnetic field configuration as an example to investigate the possible halo morphology. The predicted morphology has some different features compared to the $L_c=\infty$ scenario. The current experiments may already be able to test these features. In addition, we use a semi-analytical method to solve the anisotropic propagation equation, which offers significant convenience compared to numerical approaches.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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