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. By 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 P1.4GHz ∼ (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).

MOSS I: Double radio relics in the Saraswati supercluster

“…We reduced both the MeerKAT and GMRT data sets using the Containerized Automated Radio Astronomy Calibration (CARACal ) pipeline (Józsa et al 2020). The use of this pipeline is also mentioned in our previous work Parekh et al (2020). Briefly, the CARACal pipeline is written using the Stimela † pipelining framework, which is python-based and uses containers (Docker and Singularity) specially developed for independent radio interferometry scripting, which allows users to use general radio astronomy software.…”

Unveiling the Origin of Peculiar Diffuse Radio Emission in A1351

“…Cluster magnetic field can be approximated assuming equipartition of energy between cosmic-ray particles and magnetic field (Govoni & Feretti 2004;van Weeren et al 2009;Parekh et al 2020;Pandge et al 2022). To quantify the magnetic field at the relic location in A1351, we assumed that the system satisfies the minimum energy density condition.…”

“…− α, ν 1 , ν 2 ) = 1.57 × 10 −13 for a frequency range ν 1 (10 MHz) -ν 2 (100 GHz) and spectral index α = −1.63(Govoni & Feretti 2004), ν 0 = 1400 MHz, I 0 was estimated by dividing the flux density (10.82 mJy) of the relic at 1.4 GHz by the solid angle of 85″ × 103 ″, and the depth d of the relic was obtained in kpc taking an average of the largest (550 kpc at 1.4 GHz) and smallest (220 kpc at 1.4 GHz) linear size of the relic at 1.4 GHz. We assumed the ratio of the energy content of cosmic-ray protons and electrons k = 1(Parekh et al 2020). …”