Journal article

A study of halo and relic radio emission in merging clusters using the Murchison Widefield Array

LT George, KS Dwarakanath, M Johnston-Hollitt, HT Intema, N Hurley-Walker, ME Bell, JR Callingham, B-Q For, B Gaensler, PJ Hancock, L Hindson, AD Kapinska, E Lenc, B McKinley, J Morgan, A Offringa, P Procopio, L Staveley-Smith, RB Wayth, C Wu Show all



We have studied radio haloes and relics in nine merging galaxy clusters using the Murchison Widefield Array (MWA). The images used for this study were obtained from the GaLactic and Extragalactic All-sky MWA (GLEAM) Survey which was carried out at five frequencies, viz. 88, 118, 154, 188 and 215 MHz. We detect diffuse radio emission in eight of these clusters. We have estimated the spectra of haloes and relics in these clusters over the frequency range 80-1400 MHz; the first such attempt to estimate their spectra at low frequencies. The spectra follow a power law with a mean value of α = −1.13 ± 0.21 for haloes and α = −1.2 ± 0.19 for relics, where S ∝ να. We reclassify two of the cluster so..

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Awarded by Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO)

Awarded by Science and Technology Facilities Council

Funding Acknowledgements

We thank the referee for detailed and critical comments. This scientific work makes use of the Murchison Radio-astronomy Observatory, operated by Commonwealth Scientific and Industrial Research Organisation. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. Support for the operation of the MWA is provided by the Australian Government (National Collaborative Research Infrastructure Strategy), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the Pawsey Supercomputing Centre that is supported by the Western Australian and Australian Governments. Parts of this research were conducted by the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020. MJ-H, QZ and LH were supported in this work by grants to MJ-H from the Marsden Fund and the New Zealand Ministry of Business, Innovation and Employment.