Title:	The First Murchison Widefield Array low-frequency radio observations of cluster scale non-thermal emission: the case of Abell 3667
Authors:	Hindson, L. Johnston-Hollitt, M. Dwarakanath, K.S. Deshpande, A.A. Prabu, T. Udaya Shankar, N. Srivani, K.S. Subrahmanyan, Ravi +30 Co-authors
Keywords:	radio continuum
Issue Date:	21-Nov-2014
Publisher:	Oxford University Press for the Royal Astronomical Society
Citation:	Monthly Notices of the Royal Astronomical Society, 2014, Vol. 445, p330-346
Abstract:	We present the first Murchison Widefield Array observations of the well-known cluster of galaxies Abell 3667 (A3667) between 105 and 241 MHz. A3667 is one of the best known examples of a galaxy cluster hosting a double radio relic and has been reported to contain a faint radio halo and bridge. The origin of radio haloes, relics and bridges is still unclear, however galaxy cluster merger seems to be an important factor. We clearly detect the north-west (NW) and south-east radio relics in A3667 and find an integrated flux density at 149 MHz of 28.1 ± 1.7 and 2.4 ± 0.1 Jy, respectively, with an average spectral index, between 120 and 1400 MHz, of −0.9 ± 0.1 for both relics. We find evidence of a spatial variation in the spectral index across the NW relic steepening towards the centre of the cluster, which indicates an ageing electron population. These properties are consistent with higher frequency observations. We detect emission that could be associated with a radio halo and bridge. However, due to the presence of poorly sampled large-scale Galactic emission and blended point sources we are unable to verify the exact nature of these features.
Description:	Open Access
URI:	http://hdl.handle.net/2289/6162
ISSN:	0035-8711 1365-2966 - (online)
Alternative Location:	http://adsabs.harvard.edu/abs/2014MNRAS.445..330H http://arxiv.org/abs/1408.3167 http://dx.doi.org/10.1093/mnras/stu1669
Copyright:	2014 The authors & the Royal Astronomical Society
Appears in Collections:	Research Papers (A&A)

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