How does our choice of observable influence our estimation of the centre of a galaxy cluster? Insights from cosmological simulations
How does our choice of observable influence our estimation of the centre of a galaxy cluster? Insights from cosmological simulations
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DOI：
10.1093/mnras/stv2839
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发表时间：
2015-12
影响因子：
4.8
通讯作者：
W. Cui;C. Power;V. Biffi;S. Borgani;A. Knebe;G. Murante;D. Fabjan;G. Lewis;G. Poole
中科院分区：
文献类型：
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作者：
W. Cui;C. Power;V. Biffi;S. Borgani;A. Knebe;G. Murante;D. Fabjan;G. Lewis;G. Poole
星系团是星系演化和宇宙学理论的成熟且强大的测试平台。对聚类观测结果的准确解释往往需要对中心位置进行可靠的识别。使用从一套宇宙学模拟，我们已经探索了一系列的星系形成模型中得出的集群的统计样本，我们调查如何选择可观察到的恒星，热气体，或完整的质量分布，可以探测到的引力势的影响，这个中心的位置。我们探讨了几个措施的集群中心：最小的引力势，这将有望定义的中心，如果集群是在动态平衡;密度的峰值; BCG的中心;和X射线光度的峰值和质心。我们发现，BCG的中心更强烈的相关性与最小的引力势比X射线定义的中心，而AGN的反馈作用，以显着提高之间的偏移峰值X射线光度和最小引力势。这些结果强调了在解释集群观测时，特别是在比较理论预测和观测数据时，中心识别的重要性。
Galaxy clusters are an established and powerful test-bed for theories of both galaxy evolution and cosmology. Accurate interpretation of cluster observations often requires robust identification of the location of the centre. Using a statistical sample of clusters drawn from a suite of cosmological simulations in which we have explored a range of galaxy formation models, we investigate how the location of this centre is affected by the choice of observable - stars, hot gas, or the full mass distribution as can be probed by the gravitational potential. We explore several measures of cluster centre: the minimum of the gravitational potential, which would expect to define the centre if the cluster is in dynamical equilibrium; the peak of the density; the centre of BCG; and the peak and centroid of X-ray luminosity. We find that the centre of BCG correlates more strongly with the minimum of the gravitational potential than the X-ray defined centres, while AGN feedback acts to significantly enhance the offset between the peak X-ray luminosity and minimum gravitational potential. These results highlight the importance of centre identification when interpreting clusters observations, in particular when comparing theoretical predictions and observational data.