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|Title:||Spectral imaging of the thermal Sunyaev-Zel'dovich effect in X-COP galaxy clusters: method and validation||Authors:||Baldi, A. S.
|Issue Date:||2019||Journal:||ASTRONOMY & ASTROPHYSICS||Number:||630||First Page:||A121||Abstract:||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 by Planck. 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 of Planck beams in the chi-square minimisation of each wavelet coefficient. We applied this procedure to twelve low-redshift galaxy clusters detected by Planck with 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.||URI:||http://hdl.handle.net/20.500.12386/28886||URL:||https://www.aanda.org/articles/aa/abs/2019/10/aa36165-19/aa36165-19.html||ISSN:||0004-6361||DOI:||10.1051/0004-6361/201936165||Bibcode ADS:||2019A&A...630A.121B||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
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checked on Jan 19, 2021
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