Shaviv Nir J, Nakar Ehud, Piran Tsvi
Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Phys Rev Lett. 2009 Sep 11;103(11):111302. doi: 10.1103/PhysRevLett.103.111302. Epub 2009 Sep 10.
We show that inhomogeneity of cosmic ray (CR) sources, due to the concentration of supernova remnants (SNRs) towards the galactic spiral arms, can naturally explain the anomalous increase in the positron/electron ratio observed by PAMELA. We consistently recover the observed positron fraction between 1 and 100 GeV using SNRs as the sole source of CRs. The contribution of a few known nearby SNRs dominates the CR electron spectrum above approximately 100 GeV, leading to the relatively flat spectrum observed by Fermi and to the sharp cutoff observed by H.E.S.S.
我们表明，由于超新星遗迹（SNRs）向银河系旋臂集中，宇宙射线（CR）源的不均匀性能够自然地解释PAMELA观测到的正电子/电子比率的异常增加。我们仅将超新星遗迹作为宇宙射线的唯一来源，一致地重现了1至100 GeV之间观测到的正电子分数。少数几个已知的附近超新星遗迹的贡献在大约100 GeV以上主导了宇宙射线电子能谱，导致费米观测到相对平坦的能谱以及高能立体视野望远镜（H.E.S.S.）观测到的急剧截止。
