Low(er) frequency follow-up of 28 candidate, large-scale synchrotron sources

Abstract

We follow up on a report by Vacca et al. (2018) of 28 candidate large-scale diffuse synchrotron sources in an 8°$\times$8° area of the sky (centred at RA 5h0m0s Dec 5°48'0''). These sources were originally observed at 1.4 GHz using a combination of the single-dish Sardinia Radio Telescope (SRT) and archival NRAO VLA Sky Survey (NVSS) data. They are in an area with nine massive galaxy clusters at z $\approx$ 0.1, and are candidates for the first detection of filaments of the synchrotron cosmic web. We attempt to verify these candidate sources with lower frequency observations at 154 MHz with the Murchison Widefield Array (MWA) and at 887 MHz with the Australian Square Kilometre Array Pathfinder (ASKAP). We use a novel technique to calculate the surface brightness sensitivity of these instruments to show that our lower frequency observations, and in particular those by ASKAP, are ideally suited to detect large-scale, extended synchrotron emission. Nonetheless, we are forced to conclude that none of these sources are likely to be synchrotron in origin or associated with the cosmic web.

arXiv commentAccepted for publication in Publications of the Astronomical Society of Australia

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Cited by in corpus (7)

• Radio observations of the merging galaxy cluster system Abell 3391-Abell 3395
• SPT-CL J2032-5627: a new Southern double relic cluster observed with ASKAP
• Scalable precision wide-field imaging in radio interferometry: I. uSARA validated on ASKAP data
• MWAX: A New Correlator for the Murchison Widefield Array
• Searching for the Synchrotron Cosmic Web Again: A replication attempt
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• Low-frequency integrated radio spectra of diffuse, steep-spectrum sources in galaxy clusters: palaeontology with the MWA and ASKAP