On the giant supercluster binary-like system formed by the Corona Borealis and Abell 2142

• Published in: New astronomy Vol. 69; pp. 1 - 7
• Main Author: Pillastrini, Giovanni C. Baiesi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2019
• Subjects: Clusters; Corona Borealis Supercluster, A2142 supercluster – Cosmology; Data analysis - galaxies; Individual; Large scale structures of the Universe; Methods; Clusters; Large scale structures of the Universe; Corona Borealis Supercluster, A2142 supercluster – Cosmology; Individual; Methods; Data analysis - galaxies
• ISSN: 1384-1076; 1384-1092
• DOI: 10.1016/j.newast.2018.11.005

•The Corona Borealis/A2142 as a supercluster binary-like system has been revised.•Tidal analysis confirms a balanced gravitational interaction between them.•A peculiar velocity sample supports a flow of the A2142 region towards the CB.•The peculiar velocity sample may be biased by selection effect due to remoteness.•Even if the interaction between them is evident, the true dynamics remain unclear. The recent hypothesis of a giant supercluster binary-like structure formed by the Corona Borealis and its close companion Abell 2142 (supercluster) belongs to a little known area of investigation as the dynamics of gravitationally interacting galaxy supercluster pairs. From the observational point of view this structure approximates the configuration of a binary-like system in linear orbit interconnected by a huge filamentary structure which, if confirmed, it would be the first case to date observed at z ≥ 0.07. Given the importance to disentangle this issue, a follow-up analysis has been performed on the region constrained by the common envelop of the two superclusters in order to search for new hints to confirm their mutual gravitational interaction. Observational signatures of that interaction have been found mapping the inner peculiar motions where the observed negative peculiar velocities measured within the A2142 (supercluster) region suggest a general matter flow toward the Corona Borealis supercluster. Besides, analyzing the effects on both superclusters due to the mutual impact of the external tidal forces, turns out that their inner dynamics remain unperturbed up to the turnaround radii. Outside, where the binding forces are overlapped by the tidal ones, the outskirts of both superclusters should be unstable and subject to fragmentation. Such a scenario indicates that both superclusters interact with comparable and reciprocal tidal perturbations leaving the whole system in a substantial dynamical equilibrium. The origin of such a dynamical dichotomy would be explained either by a much more massive Corona Borealis supercluster than that estimated in the present work or by a selection effect biasing the small sample of peculiar velocities due to the remoteness of the system worsened by the large uncertainty on their measurements.