Spectral imaging of the thermal Sunyaev-Zel'dovich effect in X-COP galaxy clusters: method and validation
| Autor: | Baldi, Anna Silvia, Bourdin, Hervé, Mazzotta, Pasquale, Eckert, Dominique, Ettori, Stefano, Gaspari, Massimo, Roncarelli, Mauro |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | A&A 630, A121 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/201936165 |
| Popis: | 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. Comment: Accepted for publication in A&A |
| Databáze: | arXiv |
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