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arXiv 1209.2789astro-ph.HEastro-ph.GA
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超新星遗迹SN 1006的非热辐射再访:理论模型和H.E.S.S.结果

Nonthermal emission of supernova remnant SN 1006 revisited: theoretical model and the H.E.S.S. results

E. G. Berezhko, L. T. Ksenofontov, H. J. Voelk

摘要:

根据最近的H.E.S.S.对银河系超新星遗迹SN1006的性质进行了理论上的重新分析。结果利用非线性动力学理论计算了超新星遗迹SN 1006中宇宙射线的动量谱。模型的物理参数-质子注入率,电子-质子比和下游磁场强度-通过拟合的结果所观察到的空间积分同步辐射特性来确定。唯一剩下的未知的天文参数,星周气体数密度,是由伽马射线通量的振幅归一化到观测到的振幅确定的。非热X射线和伽马射线发射的双极形态解释的超热核的优先注入和随后的磁场放大的准平行区域的外超新星冲击。上述参数为所有现有的非热发射数据提供了改进的拟合,包括最近由H.E.S.S.检测到的TeV发射光谱,星周氢气数密度$N_H\approx 0.06 cm^{-3}$接近于从热X射线观测中得出的值。强子和轻子伽马射线的辐射强度相当。在当前时期,加速CR的总能量约为总流体动力爆炸能量的5%,并且预计将随时间以$\approx 2$的因子增加。CR逃逸的SNR的γ射线发射光谱的相关性被证明。结果的总和表明,SN 1006是一个CR源,具有高效率的核CR生产,如银河系CR源所需的,无论是在通量以及在截止能量。

英文摘要:

The properties of the Galactic supernova remnant (SNR) SN 1006 are theoretically re-analyzed in the light of the recent H.E.S.S. results. Nonlinear kinetic theory is used to determine the momentum spectrum of cosmic rays (CRs) in space and time in the supernova remnant SN 1006. The physical parameters of the model - proton injection rate, electron-to-proton ratio and downstream magnetic field strength - are determined through a fit of the result to the observed spatially-integrated synchrotron emission properties. The only remaining unknown astronomical parameter, the circumstellar gas number density, is determined by a normalization of the amplitude of the gamma-ray flux to the observed amplitude. The bipolar morphology of both nonthermal X-ray and gamma-ray emissions is explained by the preferential injection of suprathermal nuclei and subsequent magnetic field amplification in the quasi-parallel regions of the outer supernova shock. The above parameters provide an improved fit to all existing nonthermal emission data, including the TeV emission spectrum recently detected by H.E.S.S., with the circumstellar hydrogen gas number density $N_H\approx 0.06 cm^{-3}$ close to values derived from observations of thermal X-rays. The hadronic and leptonic gamma-ray emissions are of comparable strength. The overall energy of accelerated CRs at the present epoch is of the order of 5 % of the total hydrodynamic explosion energy, and is predicted to rise with time by a factor of $\approx 2$. The relevance of CR escape from the SNR for the spectrum of the gamma-ray emission is demonstrated. The sum of the results suggests that SN 1006 is a CR source with a high efficiency of nuclear CR production, as required for the Galactic CR sources, both in flux as well as in cutoff energy.

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