A powerful double radio relic system discovered in PSZ1 G108.18-11.53: Evidence for a shock with non-uniform Mach number?
A powerful double radio relic system discovered in PSZ1 G108.18-11.53: Evidence for a shock with non-uniform Mach number?
复制标题
DOI：
10.1093/mnras/stv1873
复制
发表时间：
2015-08
影响因子：
4.8
通讯作者：
F. Gasperin;H. Intema;R. V. Weeren;W. Dawson;N. Golovich;D. Wittman;A. Bonafede;M. Brüggen
中科院分区：
文献类型：
--
作者：
F. Gasperin;H. Intema;R. V. Weeren;W. Dawson;N. Golovich;D. Wittman;A. Bonafede;M. Brüggen
作者：de Gasperin， F；得主,HT;范·维伦，RJ；道森,佤邦;Golovich N;惠特曼,D;Bonafede,;Bruggen， M |摘要：©2015作者。牛津大学出版社代表皇家天文学会出版。在一些合并的星系团中发现了以射电晕和遗迹形式存在的漫射射电辐射。这些结构表明，与合并有关的激波和湍流将电子加速到相对论能量。我们在PSZ1 G108.18-11.53 （z = 0.335）中发现了一个射电遗迹+射电晕系统。这个星团拥有迄今为止发现的第二强大的双无线电遗迹系统。我们利用巨型米波射电望远镜和韦斯特伯克合成射电望远镜对PSZ1 G108.18-11.53进行了观测。我们获得了147、323、607和1380兆赫的无线电地图。我们还用凯克望远镜观测了这个星团，获得了42个星团成员的光谱红移。通过注入指数，我们得到了产生这两个射电遗迹的激波的马赫数。对于南方激波，我们发现M= 2.33-0.26+0.19，而北方激波马赫数从北部的mm = 2.20-0.14+0.07下降到南部的toM= 2.00-0.08+0.03。如果扩散激波加速理论预测的注入指数与马赫数之间的关系成立，这将是第一个观测到的马赫数沿星系团合并激波存在梯度的证据。
Author(s): de Gasperin, F; Intema, HT; van Weeren, RJ; Dawson, WA; Golovich, N; Wittman, D; Bonafede, A; Bruggen, M | Abstract: © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Diffuse radio emission in the form of radio haloes and relics has been found in a number of merging galaxy clusters. These structures indicate that shock and turbulence associated with the merger accelerate electrons to relativistic energies. We report the discovery of a radio relic + radio halo system in PSZ1 G108.18-11.53 (z = 0.335). This cluster hosts the second most powerful double radio relic system ever discovered. We observed PSZ1 G108.18-11.53 with the Giant Meterwave Radio Telescope and the Westerbork Synthesis Radio Telescope. We obtained radio maps at 147, 323, 607 and 1380 MHz. We also observed the cluster with the Keck telescope, obtaining the spectroscopic redshift for 42 cluster members. From the injection index, we obtained the Mach number of the shocks generating the two radio relics. For the southern shock, we found M = 2.33-0.26+0.19, while the northern shock Mach number goes fromM= 2.20-0.14+0.07 in the north part down toM= 2.00-0.08+0.03 in the southern region. If the relation between the injection index and the Mach number predicted by diffusive shock acceleration theory holds, this is the first observational evidence for a gradient in the Mach number along a galaxy cluster merger shock.