A rare case of FR I interaction with a hot X-ray bridge in the A2384 galaxy cluster

Abstract

Clusters of varying mass ratios can merge and the process significantly disturbs the cluster environments and alters their global properties. Active radio galaxies are another phenomenon that can also affect cluster environments. Radio jets can interact with the intra-cluster medium (ICM) and locally affect its properties. Abell 2384 (hereafter A2384) is a unique system that has a dense, hot X-ray filament or bridge connecting the two unequal mass clusters A2384(N) and A2384(S). The analysis of its morphology suggests that A2384 is a post-merger system where A2384(S) has already interacted with the A2384(N), and as a result hot gas has been stripped over a ∼ 1 Mpc region between the two bodies. We have obtained its 325 MHz GMRT data, and we detected a peculiar FR I type radio galaxy which is a part of the A2384(S). One of its radio lobes interacts with the hot X-ray bridge and pushes the hot gas in the opposite direction. This results in displacement in the bridge close to A2384(S). Based on Chandra and XMM-Newton X-ray observations, we notice a temperature and entropy enhancement at the radio lobe-X-ray plasma interaction site, which further suggests that the radio lobe is changing thermal plasma properties. We have also studied the radio properties of the FR I radio galaxy, and found that the size and radio luminosity of the interacting north lobe of the FR I galaxy are lower than those of the accompanying south lobe.

MeerKAT's discovery of a radio relic in the bimodal merging cluster A2384

“…We then obtained its GMRT 325 MHz data to study the radio environment around the cluster. We found a Fanaroff-Riley Class I (FR I henceforth) (Fanaroff & Riley 1974) radio galaxy, a member of this cluster whose northern radio lobe pushes and distorts the X-ray filament eastwards (Parekh et al 2019). Such a displacement in the X-ray filament by the radio lobe is observed here for the first time on such a large scale.…”

“…A total of 56 cluster member galaxies have been identified, and both the X-ray gas and galaxy distributions approximately define the same bimodal structure (Maurogordato et al 2011). In a previous work (Parekh et al 2019), it was observed that, in the Chandra X-ray map, there is a bend visible in the X-ray bridge ∼ 800 kpc from the X-ray peak of A2384(N). We then obtained its GMRT 325 MHz data to study the radio environment around the cluster.…”

“…3, we give each sub-band image around the central region of A2384. In Parekh et al (2019), we reported a peculiar detection of the FR I radio galaxy LEDA 851827 (J2000 RA:21h52m08.1s; Dec:-19 • 41 27 ) associated with A2384(S). Its northern radio lobe distorts the X-ray filament in the easterly direction.…”

“…A2384 is a nearby (z = 0.092), low mass, and complex bimodal (having a two component -A2384(N) and A2384(S)) merging cluster (Maurogordato et al 2011;Pranger et al 2014;Parekh et al 2019). A2384 is a peculiar cluster system that displays a dense X-ray filament (∼ 700 kpc in length) between A2384(N) and A2384(S) (Fig.…”

The Abell 3391/95 galaxy cluster system

“…According to our expectations from detailed simulations, the best places to search for LSS activity such as infalling substructures and the hot dense fraction of the WHIM is close to nearby galaxy clusters, in their outskirts, and in the presumed warm filaments connecting them. Therefore, searching in the direction of superclusters, between galaxy clusters, or within large-scale galaxy structures or galaxy pairs using X-ray and and Sunyaev-Zeldovich (SZ) observations seems to be the currently most promising way forward (e.g., Fujita et al 2008;Werner et al 2008;Fang et al 2010;Dietrich et al 2012;Planck Collaboration et al 2013;Nevalainen et al 2015;Eckert et al 2015;Bulbul et al 2016;Parekh et al 2017;Akamatsu et al 2017;Alvarez et al 2018;Tanimura et al 2019;de Graaff et al 2019;Parekh et al 2020;Tanimura et al 2020;Ghirardini et al, subm.). (Jarrett et al 2000).…”