Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223
Discovery of a possible splashback feature in the intracluster light of MACS J1149.5+2223
复制标题
DOI：
10.1093/mnras/stab2117
复制
发表时间：
2021-04
影响因子：
4.8
通讯作者：
Anthony H. Gonzalez;Tyler George;T. Connor;A. Deason;M. Donahue;M. Montes;A. Zabludoff;D. Zaritsky
中科院分区：
文献类型：
--
作者：
Anthony H. Gonzalez;Tyler George;T. Connor;A. Deason;M. Donahue;M. Montes;A. Zabludoff;D. Zaritsky
我们提出了一个分析的前沿场集群MACS J1149.5+2223（z = 0.544），它结合了新的和档案哈勃WFC 3/IR成像提供连续的径向覆盖范围从最亮的星系团（BCG）到2.8 Mpc的内光（ICL）。采用仔细处理潜在的系统偏差，并使用数据在最大半径，以确定背景天空水平，我们重建的表面亮度轮廓的半径为2百万秒差距。这个半径是单个星系团测量到的ICL的最大值。在这个半径范围内，我们测量到BCG加ICL的总光度为1.5 × 1013 L/cm。从轮廓和它的对数斜率，我们确定从BCG到ICL的过渡在r = 70 kpc。值得注意的是，我们还检测到一个明显的拐点，在1.2-1.7兆秒差距（0.37-0.52 r200米）径向仓，一个签名的恒星分布的落入焦散集中的配置文件。根据特征的形状和强度，我们将其解释为可能处于回溅半径，尽管半径小于理论预测。如果这是回溅半径，则这是ICL中的第一次此类检测，并且是单个群集的回溅半径的第一次检测。类似的分析应该可以用于其他的前沿场星系团，最终也可以用于欧几里得和罗马任务观测到的星系团。
We present an analysis of the intracluster light (ICL) in the Frontier Field Cluster MACS J1149.5+2223 (z = 0.544), which combines new and archival Hubble WFC3/IR imaging to provide continuous radial coverage out to 2.8 Mpc from the brightest cluster galaxy (BCG). Employing careful treatment of potential systematic biases and using data at the largest radii to determine the background sky level, we reconstruct the surface brightness profile out to a radius of 2 Mpc. This radius is the largest to which the ICL has been measured for an individual cluster. Within this radius, we measure a total luminosity of 1.5 × 1013 L⊙ for the BCG plus ICL. From the profile and its logarithmic slope, we identify the transition from the BCG to ICL at r ∼ 70 kpc. Remarkably, we also detect an apparent inflection in the profile centred in the 1.2–1.7 Mpc (0.37–0.52 r200m) radial bin, a signature of an infall caustic in the stellar distribution. Based upon the shape and strength of the feature, we interpret it as potentially being at the splashback radius, although the radius is smaller than theoretical predictions. If this is the splashback radius, then it is the first such detection in the ICL and the first detection of the splashback radius for an individual cluster. Similar analyses should be possible with the other Frontier Field clusters, and eventually with clusters observed by the Euclid and Roman missions.