Multifrequency radio observations of Cygnus A - Spectral aging in powerful radio galaxies
Multifrequency radio observations of Cygnus A - Spectral aging in powerful radio galaxies
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天鹅座 A 的多频射电观测 - 强大射电星系中的光谱老化
DOI：
10.1086/170813
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
J. Leahy
中科院分区：
文献类型：
--
作者：
C. Carilli;R. Perley;J. Dreher;J. Leahy
本文对天鹅座A的射电频谱进行了详细的分析，以便对同步子谱老化理论进行严格的检验。结果与强射电星系的喷流模型很好地吻合，该模型考虑了热点上的粒子加速和流出到射电叶，以及随后的同步辐射能量损失。用连续注入相对论粒子的光谱老化模型很好地描述了热点光谱。这两个热点的光谱破裂频率都在10 GHz左右。这两个热点的注入指数均为0.5，与牛顿流体中强非相对论激波的扩散激波加速一致。低频热点发射光谱低于注入指数定律。这种效应仅限于热点，并且可以用粒子分布中的低能量截断来解释。
A detailed analysis of the radio spectrum across the lobes of Cygnus A is presented in order to critically test the synchroton spectral aging theory. The results are in good agreement with the jet model for powerful radio galaxies, involving particle acceleration at the hot spots and outflow into the radio lobes, with subsequent energy loss due to synchrotron radiation. The hot spot spectra are well represented by a spectral aging model involving continuous injection of relativistic particles. Both hot spots have spectral break frequencies around 10 GHz. An injection index of 0.5 is found for both hot spots, consistent with diffusive shock acceleration at a strong nonrelativistic shock in a Newtonian fluid. The LF hot spot emission spectrum falls below the injected power law. This effect is isolated to the hot spots, and is best explained by a low-energy cutoff in the particle distribution.