MOLECULAR CLOUDS AS A PROBE OF COSMIC-RAY ACCELERATION IN A SUPERNOVA REMNANT
MOLECULAR CLOUDS AS A PROBE OF COSMIC-RAY ACCELERATION IN A SUPERNOVA REMNANT
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DOI：
10.1088/0004-637x/707/2/l179
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发表时间：
2009-11
期刊：
影响因子：
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通讯作者：
Y. Fujita;Y. Ohira;S. Tanaka;F. Takahara
中科院分区：
文献类型：
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作者：
Y. Fujita;Y. Ohira;S. Tanaka;F. Takahara
我们研究超新星遗迹 (SNR) 中的宇宙射线加速及其逃逸。我们对疏散星团 Westerlund 2 中隐藏的 SNR 和老年混合形态 SNR W 28 中的非热粒子和光子光谱进行了建模。我们假设 SNR 激波在低密度空腔中传播，该空腔是通过祖星和/或先前超新星爆炸的活动而产生和加热的。我们表明，SNR 周围宇宙射线的扩散系数小于远离它们的 ∼1%。我们将我们的预测与宇宙射线（费米和 H.E.S.S.）照射的分子云的伽马射线光谱进行比较。我们发现粒子的光谱指数为~2.3。这可能是因为粒子在谢多夫阶段结束时被加速，并且因为粒子的能量依赖逃逸和传播对光谱没有太大影响。
We study cosmic-ray acceleration in a supernova remnant (SNR) and the escape from it. We model nonthermal particle and photon spectra for the hidden SNR in the open cluster Westerlund 2, and the old-age mixed-morphology SNR W 28. We assume that the SNR shock propagates in a low-density cavity, which is created and heated through the activities of the progenitor stars and/or previous supernova explosions. We indicate that the diffusion coefficient for cosmic rays around the SNRs is less than ∼1% of that away from them. We compare our predictions with the gamma-ray spectra of molecular clouds illuminated by the cosmic rays (Fermi and H.E.S.S.). We found that the spectral indices of the particles are ∼2.3. This may be because the particles were accelerated at the end of the Sedov phase, and because energy-dependent escape and propagation of particles did not much affect the spectrum.