PROPERTIES AND SPECTRAL BEHAVIOUR OF CLUSTER RADIO HALOS
PROPERTIES AND SPECTRAL BEHAVIOUR OF CLUSTER RADIO HALOS
复制标题
星团射电晕的特性和光谱行为
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
G.Setti
中科院分区：
文献类型：
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作者：
L. Feretti;G. Brunetti;G. Giovannini;N. Kassim;E. Orrú;G.Setti
文献中提出了一些论点来支持射电晕和星团合并之间的联系。 A665 和 A2163 晕的光谱指数分布为这种联系提供了新的强有力的确认，即星团合并在射电晕的能量供应中发挥着重要作用。光谱指数的特征（平坦化和斑块）表明了辐射电子光谱的复杂形状，因此支持电子再加速模型。发现频谱较平坦的区域与最近的合并有关。相反，在未受干扰的簇区域中，频谱随着距簇中心的距离而变陡。光晕样本的积分光谱指数与星团温度的关系图表明，温度较高的星团往往会出现光谱更平坦的光晕。这种相关性提供了无线电发射与集群合并之间联系的进一步证据。
Several arguments have been presented in the literature to support the connection between radio halos and cluster mergers. The spectral index distributions of the halos in A665 and A2163 provide a new strong confirmation of this connection, i.e. of the fact that the cluster merger plays an important role in the energy supply to the radio halos. Features of the spectral index (flattening and patches) are indication of a complex shape of the radiating electron spectrum, and are therefore in support of electron reacceleration models. Regions of flatter spectrum are found to be related to the recent merger. In the undisturbed cluster regions, instead, the spectrum steepens with the distance from the cluster center. The plot of the integrated spectral index of a sample of halos versus the cluster temperature indicates that clusters at higher temperature tend to host halos with flatter spectra. This correlation provides further evidence of the connection between radio emission and cluster mergers.