Low(er) frequency follow-up of 28 candidate, large-scale synchrotron sources. (2020)

• Record Type: Journal Article
• Authors: Hodgson, Torrance; Johnston-Hollitt, Melanie; McKinley, Benjamin; Vernstrom, Tessa; Vacca, Valentina
• Is Part Of: Publications of the Astronomical Society of Australia. Volume 37(2020)
• Publication Date: 2020
• Subjects: cosmic web, -- radio continuum emission; Astronomy -- Periodicals; Southern sky (Astronomy) -- Periodicals; Astrophysics -- Periodicals; Periodicals; 520.5
• DOI: 10.1017/pasa.2020.26
• Languages: English
• ISSNs: 1323-3580

Abstract

Abstract: We follow up on a report by Vacca et al. (2018 ) of 28 candidate large-scale diffuse synchrotron sources in an 8 ° × 8 ° area of the sky (centred at RA 5 h 0 m 0 s ; Dec 5 ° 48 ʹ 00 ʹʹ ). These sources were originally observed at 1.4 GHz using a combination of the single-dish Sardinia Radio Telescope and archival NRAO VLA Sky Survey 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 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.