Unraveling the collision scenario of the dissociative galaxy cluster Abell 56 through hydrodynamic simulations

Abstract

In galaxy cluster collisions, the gas can be separated from dark matter halos. Abell~56 displays signatures of a dissociative bullet-like merger with a possible high inclination angle between the plane of orbit and the sky. Our objective is to provide a comprehensive description of the features observed in the collision scenario of Abell~56. Additionally, we aim to apply a potential weak lensing mass bias correction attributed to the merger to evaluate its impact on our findings. To investigate this, we perform tailored hydrodynamical $N$-body simulations, varying the impact parameter. We initially identified an early scenario at $0.12$\,Gyr after the central passage that reproduces some observational features. However, the mean temperature of $9.7$\,keV exceeded the observed value. Our best model corresponds to the late scenario at $0.52$\,Gyr after the pericenter, reproducing observed features of Abell~56, with an inclination of $58^\circ$. These features include the offset of $103$\,kpc between the main gas density peak and the south dark matter density peak, gas morphology, a line of sight relative velocity of $184$\,km\,s$^{-1}$, and a mean temperature of $6.7$\,keV. This late model provides a plausible scenario to describe the dynamics of Abell~56. The weak lensing mass bias did not significantly impact the overall dynamics of this cluster merger.