A SYSTEMATIC STUDY OF THE THERMAL AND NONTHERMAL EMISSION IN THE SUPERNOVA REMNANT RCW 86 WITH SUZAKU
A SYSTEMATIC STUDY OF THE THERMAL AND NONTHERMAL EMISSION IN THE SUPERNOVA REMNANT RCW 86 WITH SUZAKU
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DOI：
10.3847/1538-4357/835/1/34
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发表时间：
2016-12
期刊：
影响因子：
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通讯作者：
Y. Tsubone;M. Sawada;A. Bamba;S. Katsuda;J. Vink
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作者：
Y. Tsubone;M. Sawada;A. Bamba;S. Katsuda;J. Vink
超新星遗迹（SNRs）中的冲击波引起的扩散冲击波加速被广泛认为是银河系宇宙线的主要来源。然而，目前还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示出了具有不同空间形态的热和非热X射线发射。这些辐射分别来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，残余物提供了一个合适的实验室来测试加速效率和环境之间可能的关联。在本文中，我们提出的结果，空间分辨光谱的整个残余与朱雀。的空间分辨光谱很好地再现与同步辐射和两个组件的光学薄的热等离子体，对应于冲击星际介质（ISM）的kT为0.3 - 0.6 keV和Fe为主的喷出物的幂律的组合。研究发现，当激波速度保持较高时，非热分量的光子指数随着激波ISM的发射量的减小而减小。这一结果意味着，在RCW 86中的加速电子的最大能量在低密度和较高冲击速度区域中较高。
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 nonthermal 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 when 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.