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arXiv 1209.0300astro-ph.HE
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脉冲星风星云的时间相关模拟:扩散损失近似影响的研究

Time-dependent modeling of pulsar wind nebulae: Study on the impact of the diffusion-loss approximations

Jonatan Martin, Diego F. Torres, Nanda Rea

摘要:

在这项工作中,我们提出了一个轻子,依赖于时间的脉冲星风星云(PWNe)的模型。该模型寻求一个解决方案的轻子分布函数考虑全时间-能量依赖的扩散损失方程。依赖于时间的轻子布居通过注入、能量损失和逃逸来平衡。我们包括同步加速器,逆康普顿(IC,与宇宙微波背景以及与IR/光学光子场),自同步康普顿(SSC),和韧致辐射过程,所有没有任何辐射近似。有了这个模型,我们专注于蟹状星云作为一个例子,并提出其随时间的演变。之后,我们分析了在扩散损失方程的水平上进行的不同近似的影响,可以在文献中找到。而以前的模型忽略了逃逸项,例如,随着扩散损失方程变为平流方程,其他人将损失近似为灾难性的,因此该方程只有时间导数。还描述和计算了额外的近似值。我们表明,这是这些方法在确定的PWN演变的影响。特别是,我们发现的多波长光谱的时间依赖性的偏差和最佳拟合参数获得的完整和近似模型。

英文摘要:

In this work, we present a leptonic, time-dependent model of pulsar wind nebulae (PWNe). The model seeks a solution for the lepton distribution function considering the full time-energy dependent diffusion-loss equation. The time-dependent lepton population is balanced by injection, energy losses, and escape. We include synchrotron, inverse Compton (IC, with the cosmic-microwave background as well as with IR/optical photon fields), self-synchrotron Compton (SSC), and bremsstrahlung processes, all devoid of any radiative approximations. With this model in place we focus on the Crab nebula as an example and present its time dependent evolution. Afterwards, we analyze the impact of different approximations made at the level of the diffusion-loss equation, as can be found in the literature. Whereas previous models ignored the escape term, e.g., with the diffusion-loss equation becoming advective, others approximated the losses as catastrophic, so that the equation has only time derivatives. Additional approximations are also described and computed. We show which is the impact of these approaches in the determination of the PWN evolution. In particular, we find the time-dependent deviation of the multi-wavelength spectrum and the best-fit parameters obtained with the complete and the approximate models.

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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