论文标题
星系簇被大量相对论电子包裹
Galaxy clusters enveloped by vast volumes of relativistic electrons
论文作者
论文摘要
星系簇的中央区域被磁场渗透，并充满相对论电子。当簇合并时，磁场会被放大，并通过集群内培养基中的湍流重新加以相对论电子。这些电子达到1-10 GEV的能量，在存在磁场的情况下，会产生弥散的无线电光照，通常覆盖约1平方MPC的面积。在这里，我们报告了四个集群的观察结果，它们的无线电光环嵌入了更扩展的漫射无线电发射中，填充了比无线电光晕的30倍的体积。这些较大特征的发射率比无线电光环的发射率低约20倍。我们得出的结论是，相对论电子和磁场远远超出了无线电光环，并且集群外部区域的物理条件与无线电光晕的物理条件完全不同。
The central regions of galaxy clusters are permeated by magnetic fields and filled with relativistic electrons. When clusters merge, the magnetic fields are amplified and relativistic electrons are re-accelerated by turbulence in the intra cluster medium. These electrons reach energies of 1 -- 10 GeV and, in the presence of magnetic fields, produce diffuse radio halos that typically cover an area of ~1 square Mpc. Here we report observations of four clusters whose radio halos are embedded in much more extended, diffuse radio emission, filling a volume 30 times larger than that of radio halos. The emissivity in these larger features is about 20 times lower than the emissivity in radio halos. We conclude that relativistic electrons and magnetic fields extend far beyond radio halos, and that the physical conditions in the outer regions of the clusters are quite different from those in the radio halos.
