Utilizza questo identificativo per citare o creare un link a questo documento:
http://hdl.handle.net/20.500.12386/30412
Titolo: | LOFAR discovery of radio emission in MACS J0717.5+3745 | Autori: | Bonafede, A. Brüggen, M. Rafferty, D. Zhuravleva, I. Riseley, C. J. van Weeren, R. J. Farnes, J. S. Vazza, F. Savini, F. Wilber, A. Botteon, A. Brunetti, G. CASSANO, Rossella Ferrari, C. De Gasperin, F. Orrú, E. Pizzo, R. F. Röttgering, H. J. A. Shimwell, T. W. |
Data pubblicazione: | 2018 | Rivista: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Numero: | 478 | Fascicolo: | 3 | Da pagina:: | 2927 | Abstract: | We present results from LOFAR and GMRT observations of the galaxy cluster MACS$\,$J0717.5$+$3745. The cluster is undergoing a violent merger involving at least four sub-clusters, and it is known to host a radio halo. LOFAR observations reveal new sources of radio emission in the Intra-Cluster Medium: (i) a radio bridge that connects the cluster to a head-tail radio galaxy located along a filament of galaxies falling into the main cluster, (ii) a 1.9 Mpc radio arc, that is located North West of the main mass component, (iii) radio emission along the X-ray bar, that traces the gas in the X-rays South West of the cluster centre. We use deep GMRT observations at 608 MHz to constrain the spectral indices of these new radio sources, and of the emission that was already studied in the literature at higher frequency. We find that the spectrum of the radio halo and of the relic at LOFAR frequency follows the same power law as observed at higher frequencies. The radio bridge, the radio arc, and the radio bar all have steep spectra, which can be used to constrain the particle acceleration mechanisms. We argue that the radio bridge could be caused by the re-acceleration of electrons by shock waves that are injected along the filament during the cluster mass assembly. Despite the sensitivity reached by our observations, the emission from the radio halo does not trace the emission of the gas revealed by X-ray observations. We argue that this could be due to the difference in the ratio of kinetic over thermal energy of the intra-cluster gas, suggested by X-ray observations. | URI: | http://hdl.handle.net/20.500.12386/30412 | URL: | http://arxiv.org/abs/1805.00473v1 https://academic.oup.com/mnras/article/478/3/2927/4996356 |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/sty1121 | Bibcode ADS: | 2018MNRAS.478.2927B | Fulltext: | open |
È visualizzato nelle collezioni: | 1.01 Articoli in rivista |
File in questo documento:
File | Descrizione | Dimensioni | Formato | |
---|---|---|---|---|
1805.00473.pdf | postprint | 6.98 MB | Adobe PDF | Visualizza/apri |
sty1121.pdf | Pdf editoriale | 3.93 MB | Adobe PDF | Visualizza/apri |
Page view(s)
122
controllato il 23-apr-2024
Download(s)
26
controllato il 23-apr-2024
Google ScholarTM
Check
Altmetric
Altmetric
Tutti i documenti in DSpace sono pubblicati ad Accesso Aperto, salvo diversa indicazione per alcuni documenti specifici.