G. S. Souza | Searcharxiv

arXiv2024

Orbital motion of NGC 6166 (3C 338) and its impact on the jet morphology at kiloparsec scales

In the central region of the galaxy cluster Abell 2199 (A2199) resides the cD galaxy NGC 6166, which spatially coincides with the 3C 338 radio source. Lobes, jets, and a more detached southern structure (similar to a jet labelled as ridge) are seen at kiloparsec-scale images of 3C 338. This unusual radio morphology has led to the proposition of different hypotheses about its physical origin in the literature. In this work, we study the feasibility of a dynamical scenario where NGC 6166 moves around the X-ray inferred centre of A2199 from the point of view of three-dimensional hydrodynamic simulations. The physical characteristics of the intra-cluster medium in which the jet propagates are constrained to those derived from X-ray observations in the vicinity of NGC 6166. Possible orbits for the jet inlet region are derived from the estimated radial velocity of NGC 6166, while the jet parameters are constrained by parsec-scale interferometric radio observations and the estimated jet power of 3C 338 obtained from radio and X-ray data. Our results show that the hypothesis of NGC 6166 has been moving around the centre of A2199 during the last tens of million of years is compatible with the general radio morphology of 3C 338. Furthermore, the proposed dynamic scenario for the motion of NGC 6166 may be linked to gravitational perturbations induced by the passage of a sub-cluster of galaxies hundreds of millions of years ago.

astro-ph.HE↗

arXiv2019

Two merging galaxy clusters with very hot shock fronts observed shortly before pericentric passage

We present a detailed analysis of two merging clusters, from XMM-\textit{Newton} X-ray archival data: PLCKESZ G036.7+14.9 ($z=0.15$; hereafter G036) and PLCK G292.5+22.0 ($z=0.30$; hereafter G292). We notice that the intracluster medium is heated as a result of the merger, and we find evidence for a merger shock in the region between both subcluster haloes. X-ray observations confirm that the shocks in these systems are among the hottest known in the literature. From the ICM analysis of temperature discontinuity, the Mach numbers were determined to be $M_{\rm G036}=1.3$ and $M_{\rm G292}=1.5$ for G036 and G292, respectively. In this paper, for each cluster, we propose a hydrodynamic model for the merger as a whole, compatible with their diffuse X-ray emission and temperature maps. The simulations suggest that both clusters are observed shortly before pericentric passage. Our simulation results indicate that the merger of the G036 system is seen at an inclination of 50$^{\circ}$ (the angle between the plane of the orbit and the plane of the sky), and merely 50 Myr prior to the pericentric passage. In the case of G292, the subclusters would be merging not far from the plane of the sky ($i=18^{\circ}$) and are observed 150\,Myr before the two cores collide.

astro-ph.GA↗