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arXiv 1002.1910astro-ph.HEastro-ph.GA
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地球上的银河系电子和正电子:初级和次级通量的新估计

Galactic electrons and positrons at the Earth:new estimate of the primary and secondary fluxes

T. Delahaye, J. Lavalle, R. Lineros, F. Donato, N. Fornengo

摘要:

我们分析了地球上次级和初级起源的CR轻子通量的预测,评估了理论不确定性,并确定了它们与现有数据的一致性水平。对于传播,我们使用相对论处理的能量损失,我们提供了有用的参数化。我们通过改进我们早先导出的正电子的方法来计算次级分量。对于初选,我们估计的贡献,从天体物理来源(超新星遗迹和超新星)考虑所有已知的本地对象在2千秒差距和一个平滑的分布以外。我们发现,在5-30 GeV的能量范围内的电子通量很好地再现了一个平滑的远距离分布的源与指数$γ\sim 2.3-2.4$,而本地源占主导地位的通量在更高的能量。对于正电子来说,在5-10 GeV以上的能量下,局域中子星会产生重要的影响。影响源建模和传播的不均匀性是退化的,并且每一个都转化为关于局部通量的一个数量级的误差。在高能量的光谱形状是弱相关的本地源的光谱指数,但更强烈的距离,年龄和功率的层次结构。尽管我们描述的理论误差很大,但我们的全局和自洽分析可以解释所有可用的数据,而不会过度调整参数,因此不需要考虑任何奇异的物理学。虽然银河系CR轻子的\emph{standard paradigm}已经被很好地建立,但是我们的结果表明,由于理论上的不确定性很大,我们很难讨论任何CR轻子的\emph{standard model}。我们的分析提供了有关这些不确定性影响的详细信息,从而为未来的改进勾画出路线图。

英文摘要:

We analyse predictions of the CR lepton fluxes at the Earth of both secondary and primary origins, evaluate the theoretical uncertainties, and determine their level of consistency with respect to the available data. For propagation, we use a relativistic treatment of the energy losses for which we provide useful parameterizations. We compute the secondary components by improving on the method that we derived earlier for positrons. For primaries, we estimate the contributions from astrophysical sources (supernova remnants and pulsars) by considering all known local objects within 2 kpc and a smooth distribution beyond. We find that the electron flux in the energy range 5-30 GeV is well reproduced by a smooth distant distribution of sources with index $γ\sim 2.3-2.4$, while local sources dominate the flux at higher energy. For positrons, local pulsars have an important effect above 5-10 GeV. Uncertainties affecting the source modeling and propagation are degenerate and each translates into about one order of magnitude error in terms of local flux. The spectral shape at high energy is weakly correlated with the spectral indices of local sources, but more strongly with the hierarchy in their distance, age and power. Despite the large theoretical errors that we describe, our global and self-consistent analysis can explain all available data without over-tuning the parameters, and therefore without the need to consider any exotic physics. Though a \emph{standard paradigm} of Galactic CRs is well established, our results show that we can hardly talk about any \emph{standard model} of CR leptons, because of the very large theoretical uncertainties. Our analysis provides details about the impact of these uncertainties, thereby sketching a roadmap for future improvements.

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