MeerKAT's discovery of a radio relic in the bimodal merging cluster A2384
Abstract
We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby (z = 0.092), low-mass, complex bimodal, merging galaxy cluster that displays a dense X-ray filament (∼700 kpc in length) between A2384(N; northern cluster) and A2384(S; southern cluster). The origin of the radio relic is puzzling. Using the MeerKAT observation of A2384, we estimate that the physical size of the radio relic is 824 × 264 kpc2 and that it is a steep spectrum source. The radio power of the relic is $P_{1.4\mathrm{GHz}}\, \sim$ (3.87 ± 0.40) × 1023 W Hz-1. This radio relic could be the result of shock wave propagation during the passage of the low-mass A2384(S) cluster through the massive A2384(N) cluster, creating a trail appearing as a hot X-ray filament. In the previous GMRT 325 MHz observation, we detected a peculiar FR I radio galaxy interacting with the hot X-ray filament of A2384, but the extended radio relic was not detected; it was confused with the southern lobe of the FR I galaxy. This newly detected radio relic is elongated and perpendicular to the merger axis, as seen in other relic clusters. In addition to the relic, we notice a candidate radio ridge in the hot X-ray filament. The physical size of the radio ridge source is ∼182 × 129 kpc2. Detection of the diffuse radio sources in the X-ray filament is a rare phenomenon, and could be a new class of radio source found between the two merging clusters of A2384(N) and A2384(S).
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 2020
- DOI:
- 10.1093/mnras/staa2795
- arXiv:
- arXiv:2009.02724
- Bibcode:
- 2020MNRAS.499..404P
- Keywords:
-
- galaxies: clusters: intracluster medium;
- radio continuum: general;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 12 pages, 6 figures, accepted in MNRAS