2022/01/24 by S. W. Duchesne, M. Johnston-Hollitt, C. J. Riseley +2 · 1 voice
Physics and Astronomy · #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stac335
11 pages, 5 figures, re-submitted to MNRAS after initial review round with moderate changes
arxiv created 2022/01/24 · arxiv published 2022/01/24 · arxiv updated 2022/02/16
We present new low-frequency (ν= 88-216 MHz) observations of the complex merging galaxy cluster Abell 3266. These new observations are taken with the Murchison Widefield Array (MWA) in its Phase II 'extended', long-baseline configuration, offering the highest-resolution low-frequency view of the cluster to date. We report on the detection of four steep spectrum (α\lesssim -1 for Sν∝ να) extended radio sources within the cluster. We confirm the detection of a ∼ 570 kpc radio relic to the south of the cluster, and a possible bridge of emission connecting the relic to the cluster core. We also detect two new ultra-steep-spectrum (α\lesssim -1.7) fossil plasma sources to the north and west of the cluster centre without associated compact radio emission. A previously detected radio galaxy in the cluster is also found to have a spectrally steepening tail with steep-spectrum components highlighted by the MWA. We do not detect a giant radio halo in the cluster. After simulating a range of radio haloes at 216 MHz we place upper limits on the radio luminosity corresponding to ∼ 7.2 × 1024 W Hz-1 at 150 MHz assuming the expected 500 kpc radius, up to a factor 5 lower than expected from scaling relations. Why a giant radio halo is undetected in Abell 3266 is unclear - the timeline of the merger and overall mass of the system as determined by optical and X-ray studies suggest the foundation for a hosting system.