Simulações de sloshing do aglomerado de galáxias Abell 1644

Abstract

Recent collision events between galaxy clusters exhibit peculiar morphologies in the intracluster medium. That seems to be the case of Abell 1644, a nearby galaxy cluster (z = 0:047), composed by three main structures: the southern cluster that shows a spiral-like morphology A1644S, the northern cluster seen in X-ray observations A1644N1, and the recently discovered substructure A1644N2. By means of N-body hydrodynamical simulations, we attempt to reconstruct the dynamical history of the system. These simulations resulted in two specific scenarios: (i) The collision between A1644S and A1644N2, with an inclination in relation to the plane of the sky of 20∘. Our best model reaches the best morphology 2 Gyr after the pericentric passage, and shows a good agreement with observations; (ii) The collision between A1644S and A1644N1. This scenario was evaluated in two instants of time: in the first passage after the pericentric passage; and after apoapsis, when the cluster returns when reaching the maximum separation. This approach of collision between A1644S/N1 did not give rise to results as satisfactory as the scenario A1644S/N2, due to great disturbances in density and mismatching temperature maps. As a complementary study, we perform a three-cluster simulation using as base the best-fitting model A1644S/N2. We tried to reproduce the current state of A1644 with the three main structures, resulting in a good agreement to the global morphology of the observations. Thus, we find that the more likely scenario is a collision between A1644S and A1644N2, where A1644N1 may be present as long as it does not greatly interfere in the formation of the spiral feature.