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arXiv 1010.3477astro-ph.HE
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用基于Gamma-ray观测的注入模型解释Cosmic Ray e^+/(e^- + e^+)和pbar/p比值

Cosmic Ray e^+/(e^- + e^+) and pbar/p Ratios Explained by an Injection Model Based on Gamma-ray Observations

S. -H. Lee, T. Kamae, L. Baldini, F. Giordano, M. -H. Grondin, L. Latronico, M. Lemoine-Goumard, C. Sgró, T. Tanaka, Y. Uchiyama

摘要:

我们提出了一个模型的宇宙射线注入到银河系空间的基础上最近的伽马射线观测超新星遗迹(SNRs)和脉冲星风星云(PWNe)的费米大面积望远镜和成像大气切伦科夫望远镜。我们假设来自银河系SNR系综的核粒子和电子(e^-)以及来自银河系PWNe系综的电子和正电子(e^+)的稳态注入,并根据伽马射线观测和最近发展的演化和发射模型推断它们的注入光谱。假设SNR和PWNe的集合共享相同的空间分布。评估可能的二次CR贡献致密的分子云与信噪比相互作用。星际空间中的CR传播由GALPROP处理。不同的底层源分布模型和星系晕的大小来估计模型的系统不确定性。我们证明,这个基于观测的模型相当好地再现了帕梅拉和其他先前任务报告的正电子分数e^+/(e^- + e^+)和反质子与质子的比率,而不需要任何推测来源。然而,费米测量的总e^- + e^+能谱与我们的模型在20 GeV以下的能谱之间仍然存在差异,我们讨论了可能的原因。银河CR的重要数量,包括他们的能量注入,平均寿命,平均气体密度沿其典型的传播路径进行了估计。

英文摘要:

We present a model of cosmic ray injection into the Galactic space based on recent gamma-ray observations of supernova remnants (SNRs) and pulsar wind nebulae (PWNe) by the Fermi Large Area Telescope and imaging atmospheric Cherenkov telescopes. Steady-state (SS) injection of nuclear particles and electrons (e^-) from the Galactic ensemble of SNRs, and electrons and positrons (e^+) from the Galactic ensemble of PWNe are assumed, with their injection spectra inferred under guidance of gamma-ray observations and recent development of evolution and emission models. The ensembles of SNRs and PWNe are assumed to share the same spatial distributions. Assessment of possible secondary CR contribution from dense molecular clouds interacting with SNRs is also given. CR propagation in the interstellar space is handled by GALPROP. Different underlying source distribution models and Galaxy halo sizes are employed to estimate the systematic uncertainty of the model. We show that this observation-based model reproduces the positron fraction e^+/(e^- + e^+) and antiproton-to-proton ratio reported by Pamela and other previous missions reasonably well, without calling for any speculative sources. A discrepancy remains, however, between the total e^- + e^+ spectrum measured by Fermi and our model below 20GeV, for which the potential causes are discussed. Important quantities for Galactic CRs including their energy injection, average lifetime, and mean gas density along their typical propagation path are also estimated.

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