标题： 通过 Suzaku 对超新星遗迹 RCW 86 中的热辐射和非热辐射的系统研究 显示英文标题

标题： A Systematic Study of the Thermal and Nonthermal Emission in the Supernova Remnant RCW 86 with Suzaku

摘要： 由超新星遗迹（SNRs）中的激波产生的扩散性激波加速被广泛认为是银河系宇宙射线的主要来源。 然而，尚不清楚是什么决定了加速粒子的最大能量。 周围环境可能是关键参数之一。 SNR RCW 86同时显示出具有不同空间形态的热性和非热性X射线辐射。 这些辐射分别起源于激波加热的等离子体和加速的电子，它们的强度反映了它们的密度分布。 因此，该遗迹提供了一个适合测试加速效率与环境之间可能关联的实验室。 在本文中，我们展示了利用Suzaku对整个遗迹进行的空间分辨光谱结果。 空间分辨的光谱通过同步辐射的幂律和两个组分的光学薄热等离子体的组合得到了很好的拟合，分别对应于具有kT为0.3-0.6 keV的激波星际介质（ISM）和以铁为主的抛射物。 发现非热成分的光子指数随着激波星际介质的发射度降低而减小，其中激波速度保持较高。 这一结果表明，在低密度和高激波速度区域，RCW 86中加速电子的最大能量更高。 显示英文摘要

摘要： Diffusive shock acceleration by the shockwaves in supernova remnants (SNRs) is widely accepted as the dominant source for Galactic cosmic rays. However, it is unknown what determines the maximum energy of accelerated particles. The surrounding environment could be one of the key parameters. The SNR RCW 86 shows both thermal and non-thermal X-ray emission with different spatial morphologies. These emission originate from the shock-heated plasma and accelerated electrons respectively, and their intensities reflect their density distributions. Thus, the remnant provides a suitable laboratory to test possible association between the acceleration efficiency and the environment. In this paper, we present results of spatially resolved spectroscopy of the entire remnant with Suzaku. The spacially-resolved spectra are well reproduced with a combination of a power-law for synchrotron emission and a two-component optically thin thermal plasma, corresponding to the shocked interstellar medium (ISM) with kT of 0.3-0.6 keV and Fe-dominated ejecta. It is discovered that the photon index of the nonthermal component becomes smaller with decreasing the emission measure of the shocked ISM, where the shock speed has remained high. This result implies that the maximum energy of accelerated electrons in RCW 86 is higher in the low-density and higher shock speed regions.