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http://hdl.handle.net/20.500.12386/30391
Title: | First evidence of diffuse ultra-steep-spectrum radio emission surrounding the cool core of a cluster | Authors: | Savini, F. Bonafede, A. Brüggen, M. van Weeren, R. Brunetti, G. Intema, H. Botteon, A. Shimwell, T. Wilber, A. Rafferty, D. Giacintucci, S. CASSANO, Rossella Cuciti, V. de Gasperin, F. Röttgering, H. Hoeft, M. White, G. |
Issue Date: | 2018 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 478 | Issue: | 2 | First Page: | 2234 | Abstract: | Diffuse synchrotron radio emission from cosmic ray electrons is observed at the centre of a number of galaxy clusters. These sources can be classified either as giant radio haloes, which occur in merging clusters, or as mini haloes, which are found only in cool-core clusters. In this paper, we present the first discovery of a cool-core cluster with an associated mini halo that also shows ultra-steep-spectrum emission extending well beyond the core that resembles radio halo emission. The large-scale component is discovered thanks to LOFAR observations at 144 MHz. We also analyse GMRT observations at 610 MHz to characterize the spectrum of the radio emission. An X-ray analysis reveals that the cluster is slightly disturbed, and we suggest that the steep-spectrum radio emission outside the core could be produced by a minor merger that powers electron re-acceleration without disrupting the cool core. This discovery suggests that, under particular circumstances, both a mini halo and giant halo could co-exist in a single cluster, opening new perspectives for particle acceleration mechanisms in galaxy clusters. | URI: | http://hdl.handle.net/20.500.12386/30391 | URL: | https://academic.oup.com/mnras/article-abstract/478/2/2234/4990955?redirectedFrom=fulltext | ISSN: | 0035-8711 | DOI: | 10.1093/mnras/sty1125 | Bibcode ADS: | 2018MNRAS.478.2234S | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
Files in This Item:
File | Description | Size | Format | |
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1805.01900.pdf | postprint | 3.69 MB | Adobe PDF | View/Open |
sty1125.pdf | Pdf editoriale | 8.8 MB | Adobe PDF | View/Open |
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