文章基本信息

标题：Spectral imaging of the thermal Sunyaev–Zel’dovich effect in X-COP galaxy clusters: method and validation
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作者：A. S. Baldi ; H. Bourdin ; P. Mazzotta 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2019
卷号：630
页码：1-10
DOI：10.1051/0004-6361/201936165
语种：English
出版社：EDP Sciences
摘要：The imaging of galaxy clusters through the Sunyaev–Zel’dovich effect is a valuable tool to probe the thermal pressure of the intra-cluster gas, especially in the outermost regions where X-ray observations suffer from photon statistics. For the first time, we produce maps of the Comptonization parameter by applying a locally parametric algorithm for sparse component separation to the latest frequency maps released byPlanck. The algorithm takes into account properties of real cluster data through the two-component modelling of the spectral energy density of thermal dust, and the masking of bright point sources. Its robustness has been improved in the low signal-to-noise regime, thanks to the implementation of a deconvolution ofPlanckbeams in the chi-square minimisation of each wavelet coefficient. We applied this procedure to twelve low-redshift galaxy clusters detected byPlanckwith the highest signal-to-noise ratio, considered in the XMM Cluster Oustkirts Project (X-COP). Our images show the presence of anisotropic features, such as small-scale blobs and filamentary substructures that are located in the outskirts of a number of clusters in the sample. The significance of their detection is established via a bootstrap-based procedure we propose here for the first time. In particular, we present a qualitative comparison with X-ray data for two interesting systems, namely A2029 and RXCJ1825. Our results are in agreement with the features detected in the outskirts of the clusters in the two bands.
关键词：entechniques: image processinggalaxies: clusters: generalgalaxies: clusters: intracluster medium