Brightest cluster galaxies trace weak lensing mass bias and halo triaxiality in the three hundred project
Brightest cluster galaxies trace weak lensing mass bias and halo triaxiality in the three hundred project
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最亮的星团星系在三百计划中追踪弱透镜质量偏差和晕三轴性
DOI：
10.1093/mnras/stac997
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发表时间：
2022
影响因子：
4.8
通讯作者：
Yepes, Gustavo
中科院分区：
文献类型：
--
作者：
Herbonnet, Ricardo;Crawford, Adrian;Avestruz, Camille;Rasia, Elena;Giocoli, Carlo;Meneghetti, Massimo;von der Linden, Anja;Cui, Weiguang;Yepes, Gustavo
星系团具有三轴物质分布。弱透镜信号是宇宙学研究中的一个重要组成部分，它测量视线上所有物质的投影质量，因此会随着星系团的方向变化。研究表明，星系团中心最亮的星系团星系(BCG)的形状跟踪了底层的光晕形状，这使得一种方法能够解释投影效应。我们使用了324个来自三百计划的红移在0.1到0.6之间的模拟星团来量化卡介苗和晕的方向和形状之间的相关性。我们发现，晕和它们嵌入的BCG是对齐的，它们的主轴之间平均有20度的∼角。弱透镜星团质量估计的偏差与晕和BCG的方向有关。模拟观测，我们计算了BCG的投影形状，作为BCG取向的度量，并发现它与松弛星团的弱透镜质量最相关。我们还测试了从BCG质量等值线测量的2D团簇松弛代理。与总恒星质量相比，投射的BCG核心中恒星质量的浓度提供了BCG取向的替代指标。我们发现，该浓度与弱透镜质量偏差无关，但与真正的晕质量有关。这些结果表明，大样本松弛星团的BCG形状和取向可以为改进弱透镜质量估计提供信息。
Galaxy clusters have a triaxial matter distribution. The weak-lensing signal, an important part in cosmological studies, measures the projected mass of all matter along the line of sight, and therefore changes with the orientation of the cluster. Studies suggest that the shape of the brightest cluster galaxy (BCG) in the centre of the cluster traces the underlying halo shape, enabling a method to account for projection effects. We use 324 simulated clusters at four redshifts between 0.1 and 0.6 from ‘The Three Hundred Project’ to quantify correlations between the orientation and shape of the BCG and the halo. We find that haloes and their embedded BCGs are aligned, with an average ∼20 degree angle between their major axes. The bias in weak lensing cluster mass estimates correlates with the orientation of both the halo and the BCG. Mimicking observations, we compute the projected shape of the BCG, as a measure of the BCG orientation, and find that it is most strongly correlated to the weak-lensing mass for relaxed clusters. We also test a 2D cluster relaxation proxy measured from BCG mass isocontours. The concentration of stellar mass in the projected BCG core compared to the total stellar mass provides an alternative proxy for the BCG orientation. We find that the concentration does not correlate to the weak-lensing mass bias, but does correlate with the true halo mass. These results indicate that the BCG shape and orientation for large samples of relaxed clusters can provide information to improve weak-lensing mass estimates.