AI 中文总结
本研究结合MeerKAT与LOFAR的多频射电数据及X射线存档数据，在晃动冷核星系团2A 0335+096中发现嵌有微晕的510 kpc大尺度射电晕，为星系团晃动驱动湍流加速的理论提供了观测支持。
AI 中文摘要
星系团中射电晕与微晕的现有认知图景比以往认为的更模糊，边界也远没那么清晰。虽然二者都追踪星系团内介质（ICM）中的宇宙线电子和磁场，但我们对这些源的能量供给机制、自身性质及其与星系团动力学的关联的认识仍不完整。我们展示了对存在晃动现象的冷核星系团2A 0335+096的最新深度MeerKAT L波段（856−1712 MHz）观测数据——该观测是“MeerKAT-meets-LOFAR”微晕普查项目的一部分，同时还使用了重新处理的LOFAR 120−168 MHz LOw Frequency ARray 两米巡天（LOFAR Two-metre Sky Survey）数据。我们生成了高灵敏度射电连续谱图像，基于这些图像开展了光谱分析，并结合重新处理的XMM-Newton存档数据，对热与非热性质进行了对比。我们的MeerKAT数据显示，已知的微晕嵌在一个尺度达510 kpc的大尺度射电晕中，该星系团存在晃动现象，不过LOFAR仅探测到了内部的微晕。我们测得微晕的典型陡谱指数为α= -1.20 ± 0.09；LOFAR未探测到更大尺度的晕，表明其谱指数不陡于-1.2。我们的结果与“星系团势阱内的晃动驱动湍流（再）加速”的解释大体一致。这项工作强调，需要将深度、高动态范围的多频射电观测与高质量X射线观测相结合，以完善我们对射电晕性质与星系团动力学之间关联的理解。
英文摘要
The emerging picture of radio haloes and mini-haloes in galaxy clusters is more blurred and far less distinct than once thought. While both trace cosmic ray electrons and magnetic fields in the intracluster medium (ICM), our knowledge of the mechanisms powering these sources, their properties and their connection to cluster dynamics, is incomplete. We present new deep MeerKAT L-band (856$-$1712\,MHz) observations of the sloshing cool-core cluster 2A~0335+096, performed as part of the ``MeerKAT-meets-LOFAR'' mini-halo census, as well as reprocessed LOFAR 120$-$168\,MHz LOFAR Two-metre Sky Survey data. We present highly sensitive radio continuum images, from which we perform a spectral analysis and a comparison of the thermal and non-thermal properties using reprocessed archival \textit{XMM-Newton} data. Our MeerKAT data reveal that the known mini-halo is embedded in a large-scale radio halo spanning up to 510\,kpc in this sloshing cluster, although only the inner mini-halo is detected by LOFAR. We find a typical steep spectrum of $α= -1.20 \pm 0.09$ for the mini-halo; the non-detection of the larger-scale halo by LOFAR indicates a spectral index no steeper than $-1.2$. Our results are broadly consistent with an interpretation of turbulent (re-)acceleration powered by sloshing within the cluster potential well. This work emphasises the need for using deep, high-dynamic multi-frequency radio observations in conjunction with high-quality X-ray observations to complete our understanding of the connection between radio halo properties and cluster dynamics.
CommentsAccepted for publication in A&A. Main article is 13 pages, appendix 3 pages
