An off-axis galaxy cluster merger: Abell 0141

Abstract

We present structural analysis results of Abell 0141 (z = 0.23) based on X-ray data. The X-ray luminosity map demonstrates that Abell 0141 (A0141) is a bimodal galaxy cluster, which is separated on the sky by similar to 0.65 Mpc with an elongation along the north south direction. The optical galaxy density map also demonstrates this bimodality. We estimate sub-cluster ICM temperatures of 5.17(-0.19)(+0.20) keV for A0141N and 5.23(-0.23)(+0.24) keV for A0141S. We obtain X-ray morphological parameters w = 0.034 +/- 0.004, c = 0.113 +/- 0.004, and w = 0.039 +/- 0.004, c = 0.104 +/- 0.005 for A0141N and A0141S, respectively. The resulting X-ray morphological parameters indicate that both sub-clusters are moderately disturbed non-cool core structures. We find a slight brightness jump in the bridge region, and yet, there is still an absence of strong X-ray emitting gas between sub-clusters. We discover a significantly hotspot (similar to 10 keV) between sub-clusters, and a Mach number M = 1.694(-0.37)(+0.40) is obtained by using the temperature jump condition. However, we did not find direct evidence for shock-heating between sub clusters. We estimate the sub-clusters' central entropies as K-0 > 100 keV cm(2), which indicates that the sub-clusters are not cool cores. We find some evidence that the system undergoes an off-axis collision; however, the cores of each sub-clusters have not yet been destroyed. Due to the orientation of X-ray tails of sub-clusters, we suggest that the northern sub-cluster moves through the south-west direction, and the southern cluster moves through the north-east direction. In conclusion, we are witnessing an earlier phase of close core passage between sub-clusters.