Constraints on the magnetic field in the intercluster bridge A399-A401
Constraints on the magnetic field in the intercluster bridge A399-A401
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簇间桥 A399-A401 中磁场的约束
DOI：
10.1051/0004-6361/202346303
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发表时间：
2023
影响因子：
6.5
通讯作者：
Balboni M
中科院分区：
文献类型：
--
作者：
Balboni M
星系团合并是宇宙结构形成的自然结果。此类事件涉及过程中大量能量（1063 erg）的耗散。这种能量的一部分可以被引导到粒子加速和磁场放大中，从而增强团内和团间环境的非热发射。最近，低频观测导致检测到一个连接两个合并星系团阿贝尔399和阿贝尔401的弥漫同步辐射桥。这一结果为星系团之间的相对论粒子和磁场提供了明确的观测证据。在这项工作中，我们使用低频阵列（LOFAR）的观测在144 MHz的A399-A401桥区的极化发射的第一次研究。桥区没有检测到偏振发射。假设一个模型，其中极化是由多个冲击产生的，去极化可以是由于法拉第分散在前景介质相对于冲击。我们将其法拉第色散限制为大于0.10 rad m− 2（置信度为95%），这相当于桥区的平均磁场大于0.46 nG（如果我们包括被银河辐射污染的法拉第光谱区域，则为0.41 nG）。这一结果在很大程度上与百万秒差距区域的数值模拟预测一致，在这些区域，气体密度比平均气体密度高约300倍。
Galaxy cluster mergers are natural consequences of structure formation in the Universe. Such events involve the dissipation of a large amount of energy (∼1063erg) during the process. Part of this energy can be channelled in particle acceleration and magnetic field amplification, enhancing non-thermal emission of the intra- and intercluster environment. Recently, low-frequency observations led to the detection of a bridge of diffuse synchrotron emission connecting two merging galaxy clusters, Abell 399 and Abell 401. This result provides clear observational evidence of relativistic particles and magnetic fields in between clusters. In this work, we used LOw Frequency ARray (LOFAR) observations at 144 MHz to study the polarised emission in the A399–A401 bridge region for the first time. No polarised emission was detected from the bridge region. Assuming a model where polarisation is generated by multiple shocks, depolarisation can be due to Faraday dispersion in the foreground medium with respect to the shocks. We constrained its Faraday dispersion to be greater than 0.10 rad m−2at 95% confidence level, which corresponds to an average magnetic field in the bridge region of greater than 0.46 nG (or 0.41 nG if we include regions of the Faraday spectrum that are contaminated by Galactic emission). This result is largely consistent with the predictions from numerical simulations for megaparsec regions where the gas density is about 300 times higher than the mean gas density.
RM-Tools：旋转测量 (RM) 合成和 Stokes QU 拟合
DOI：
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发表时间：
2020
期刊：
影响因子：
--
作者：
C. Purcell;Cameron Van Eck;J. West;Xiaohui Sun;B. Gaensler
通讯作者：
B. Gaensler
DOI：
10.1136/ebmh.11.4.102
发表时间：
2008-10
期刊：
Evidence Based Mental Health
影响因子：
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作者：
P. Cochat;L. Vaucoret;J. Sarles
通讯作者：
P. Cochat;L. Vaucoret;J. Sarles