AI 中文总结
研究阿贝尔2244星系团双组分弥漫射电辐射，结合高灵敏度射电与X射线观测及模拟观测，确定其光谱指数等特性，发现外部组分特征介于射电晕和巨晕之间，推测其可能来源，排除低分辨率下微弱源致发射的可能。
AI 中文摘要
近年来，在非合并和合并系统中都观测到了拥有多组分晕的星系团。这些多组分晕的存在表明单一组分之间没有明显区别。阿贝尔2244是一个中等质量星系团，拥有双组分弥漫射电辐射。本文旨在深入研究该弥漫射电辐射，以确定其起源并描述其主要射电特性。我们展示了对阿贝尔2244星系团的低频阵列（LOFAR）高频波段（HBA）、麦克斯韦望远镜（MeerKAT）超高频波段和L波段观测。将高灵敏度射电数据与XMM-牛顿深X射线观测相结合来研究弥漫射电辐射的性质，还用模拟LOFAR观测来研究微弱射电源发射的污染。我们发现两个组分的综合光谱指数\(\alpha^{1279}_{144}=0.9\pm0.1\)，只有射电晕在更高频率处光谱变陡。这些值与在受干扰的大质量星系团中观测到的光谱指数相当。外部组分与射电晕的射电- X射线相关性不同，表明其物理起源不同。通过分析弥漫发射的物理和形态特性，我们发现发射外部组分的特征介于射电晕和已知巨晕之间。因此，我们推测该源要么是由小合并相互作用引起的形态受干扰的射电晕，要么是巨晕，但无法最终分类。从模拟观测来看，低分辨率下发射由微弱源引起的可能性不大。
英文摘要
Context. In recent years, clusters have been observed that host multi-component haloes, both in non-merging and merging systems. The existence of these multi-component haloes suggests that there is no clear distinction between the single components. Aims. Abell 2244 is an intermediate-mass cluster that hosts a double component diffuse radio emission. The aim of this paper is to carry out a in-depth study of the diffuse radio emission to constrain its origin and characterize its main radio properties. Methods. In this work we present LOFAR HBA, MeerKAT UHF, and L-band observations of the cluster Abell 2244. We investigated the nature of the diffuse radio emission, combining high sensitivity radio data with XMM-Newton deep X-ray observations. We also used mock LOFAR observations to investigate contamination of the emission from faint radio sources. Results. We find an integrated spectral index of $α^{1279}_{144} = 0.9 \pm 0.1$ for both components, where only the radio halo shows spectral steepening at higher frequencies. These values are comparable with the spectral indices observed in disturbed massive clusters. The outer component does not follow the same radio X-ray correlation as the radio halo, which suggests a different physical origin. Conclusions. By analysing the physical and morphological properties of the diffuse emission, we find that the characteristics of the outer component of the emission are intermediate between those of radio haloes and of known megahaloes. Hence, we speculate that the source is either a morphologically disturbed radio halo, caused by a minor merger interaction, or a megahalo but we cannot reach a final classification. From the mock observations, we find that it is unlikely that the emission is caused by faint sources at low resolutions.
Comments18 pages, 19 figures. Accepted for publication in A&A
DOI：10.1051/0004-6361/202659157
