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arXiv 1301.7499astro-ph.HE
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年轻超新星遗迹非热电子能谱截止形状的同步辐射X射线诊断

Synchrotron X-ray diagnostics of cutoff shape of nonthermal electron spectrum at young supernova remnants

Ryo Yamazaki, Yutaka Ohira, Makoto Sawada, Aya Bamba

摘要:

同步加速器X射线是研究年轻超新星遗迹(SNRs)电子加速的有用工具。目前,由于SNR冲击周围的磁场配置是不确定的,它是不清楚的电子加速是由SNR年龄,同步加速器冷却,甚至逃逸的加速区的限制。我们研究了加速机制是否可以通过最大能量附近的电子谱的截止形状来约束。我们推导出的截止形状的解析公式,在每种情况下,最大的电子能量是由SNR年龄,同步辐射冷却和逃逸的冲击。它们与电子扩散系数的能量依赖性有关。接下来,我们讨论是否可以提供的截止形状的信息,在不久的将来,这将简单地给出在软,硬X射线波段的光子指数和通量比的观测。我们发现,如果幂律指数的电子光谱是独立的其他观测确定的,那么我们可以通过比较理论预测的光子指数和/或通量比与观测数据,将测量NuSTAR和/或ASTRO-H约束截止形状。这一研究有助于理解加速机制。特别是,它将提供另一个独立的约束磁场强度周围的冲击信噪比。

英文摘要:

Synchrotron X-rays can be a useful tool to investigate electron acceleration at young supernova remnants (SNRs). At present, since the magnetic field configuration around the shocks of SNRs is uncertain, it is not clear whether electron acceleration is limited by SNR age, synchrotron cooling, or even escape from the acceleration region. We study whether the acceleration mechanism can be constrained by the cutoff shape of the electron spectrum around the maximum energy. We derive analytical formulae of the cutoff shape in each case where the maximum electron energy is determined by SNR age, synchrotron cooling and escape from the shock. They are related to the energy dependence of the electron diffusion coefficient. Next, we discuss whether information on the cutoff shape can be provided by observations in the near future which will simply give the photon indices and the flux ratios in the soft and hard X-ray bands. We find that if the power-law index of the electron spectrum is independently determined by other observations, then we can constrain the cutoff shape by comparing theoretical predictions of the photon indices and/or the flux ratios with observed data which will be measured by NuSTAR and/or ASTRO-H. Such study is helpful in understanding the acceleration mechanism. In particular, it will supply another independent constraint on the magnetic field strength around the shocks of SNRs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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