A low-frequency sub-arcsecond view of powerful radio galaxies in rich-cluster environments: 3C 34 and 3C 320
A low-frequency sub-arcsecond view of powerful radio galaxies in rich-cluster environments: 3C 34 and 3C 320
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丰富星团环境中强大射电星系的低频亚角秒视图：3C 34 和 3C 320
DOI：
10.1093/mnras/stad395
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发表时间：
2023
影响因子：
4.8
通讯作者：
Mahatma V
中科院分区：
文献类型：
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作者：
Mahatma V
射电星系物理模型主要基于对其喷流、热点和叶的高频（≥1ghz）观测。没有高分辨率的低频观测，我们对射电星系的动力学及其与环境的相互作用的理解是有限的。在这里，我们展示了第一张亚弧秒（0.3弧秒）分辨率的144 MHz图像，这两个强大的射电星系位于丰富的星团环境中，即3C 34和3C 320。我们首次在低频率下探测到这些物体中的大量结构，包括两个源中横跨叶底部的惊人的大细丝，这些细丝在空间上与周围介质中的密集区域相关。对于3C 34，我们报告了中心长丝区域的光谱变平，这表明长丝的起源与大规模有序磁场的存在有关。我们还报道了东叶漫射辐射的周期性总强度和光谱指数带，这是第一次在射电星系叶中看到。热点配合物被分解成多个不同结构和光谱指数的片段；我们讨论了粒子加速和射流终止模型的意义。我们发现，在热点结构的光谱行为中，最平滑的梯度表明，与简单模型相比，粒子加速（如果存在）可能发生在整个复杂模型中，但不同的射流终止模型可能适用于两个源。
Models of radio galaxy physics have been primarily based on high frequency (≥1 GHz) observations of their jets, hotspots, and lobes. Without highly resolved low-frequency observations, which provide information on older plasma, our understanding of the dynamics of radio galaxies and their interaction with their environment is limited. Here, we present the first sub-arcsecond (0.3 arcsec) resolution images at 144 MHz of two powerful radio galaxies situated in rich cluster environments, namely 3C 34 and 3C 320, using the International Low Frequency Array Telescope. We detect for the first time at low frequencies a plethora of structures in these objects, including strikingly large filaments across the base of the lobes in both sources, which are spatially associated with dense regions in the ambient medium. For 3C 34, we report a spectral flattening in the region of the central filament, suggesting that the origin of the filaments is related to the presence of large-scale ordered magnetic fields. We also report periodic total intensity and spectral index banding of diffuse emission in the eastern lobe, seen for the first time in radio galaxy lobes. The hotspot complexes are resolved into multiple fragments of varying structure and spectral index; we discuss the implications for particle acceleration and jet termination models. We find at most smooth gradients in the spectral behaviour of the hotspot structure suggesting that particle acceleration, if present, may be occurring throughout the complex, in contrast to simple models, but different jet termination models may apply to both sources.