Secondary cosmic-ray nuclei from supernova remnants and constraints on the propagation parameters
Secondary cosmic-ray nuclei from supernova remnants and constraints on the propagation parameters
复制标题
超新星遗迹的次级宇宙线核和传播参数的限制
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
F. Donato
中科院分区：
文献类型：
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作者：
N. Tomassetti;F. Donato
语境。二次与一次硼碳 (B/C) 比率广泛用于研究银河系中的宇宙射线 (CR) 传播过程。通常假设 Li-Be-B 等次级核完全是由较重的 CR 核与星际介质 (ISM) 碰撞产生的。目标。我们研究在次级核也可以由银河源产生或加速的情况下的 CR 传播。我们考虑超新星遗迹 (SNR) 内的强子相互作用过程以及强冲击中背景 CR 的再加速。我们研究它们对当前和未来数据中传播参数确定的影响。方法。分析计算是在扩散激波加速理论和 CR 输运扩散晕模型的框架下进行的。使用 B/C 比率的现有数据以及 AMS-02 实验预期的模拟数据进行统计分析，以确定传播参数及其不确定性范围。结果。 SNR 发射的 Li-Be-B 核的光谱比 CR 与 ISM 碰撞产生的光谱更难。由于源中的散裂和再加速，次级与初级的比率在 ~TeV/n 能量下显着变平。这两种机制是相辅相成的，并且取决于扩展残余物周围局部 ISM 的特性。 SNR 的二次产生对于密集背景介质 n1 1c m -3 很重要，而重新加速的 CR 量与扩展到稀薄介质 n1 0. 1c m -3 的 SNR 相关。由于这些影响，扩散参数 δ 可能被低估约 5-15%。我们的估计表明，AMS-02 口径的实验可以限制关键传播参数，同时打破多种 B/C 一致模型的源传输简并性。结论。鉴于正在进行的实验所预期的数据精度，应考虑二次核的 SNR 产生/加速（如果有），以防止 CR 传输参数可能出现错误确定。
Context. The secondary-to-primary boron-to-carbon (B/C) ratio is widely used to study the cosmic-ray (CR) propagation processes in the Galaxy. It is usually assumed that secondary nuclei such as Li-Be-B are generated entirely by collisions of heavier CR nuclei with the interstellar medium (ISM). Aims. We study the CR propagation under a scenario where secondary nuclei can also be produced or accelerated by Galactic sources. We consider the processes of hadronic interactions inside supernova remnants (SNRs) and the re-acceleration of background CRs in strong shocks. We investigate their impact in the propagation parameter determination within present and future data. Methods. Analytical calculations are performed in the frameworks of the diffusive shock acceleration theory and the diffusive halo model of CR transport. Statistical analyses are performed to determine the propagation parameters and their uncertainty bounds using existing data on the B/C ratio, as well as the simulated data expected from the AMS-02 experiment. Results. The spectra of Li-Be-B nuclei emitted from SNRs are harder than those due to CR collisions with the ISM. The secondary-toprimary ratios flatten significantly at ∼TeV/n energies, both from spallation and re-acceleration in the sources. The two mechanisms are complementary to each other and depend on the properties of the local ISM around the expanding remnants. The secondary production in SNRs is significant for dense background media, n1 1c m −3 , while the amount of re-accelerated CRs is relevant to SNRs expanding into rarefied media, n1 0. 1c m −3 . Owing to these effects, the diffusion parameter δ may be underestimated by a factor of ∼5–15%. Our estimations indicate that an experiment of the AMS-02 caliber can constrain the key propagation parameters, while breaking the source-transport degeneracy for a wide class of B/C-consistent models. Conclusions. Given the precision of the data expected from ongoing experiments, the SNR production/acceleration of secondary nuclei should be considered, if any, to prevent a possible mis-determination of the CR transport parameters.