Structure and kinematics of the interacting group NGC 5098/5096

Most galaxies in the Universe are found in groups, which have various morphologies and dynamical states. Studying how groups evolve is an important step for our understanding in both large-scale structure formation and galaxy evolution. We analysed the system composed by two groups at z = 0.037, NGC 5098, a group dominated by a pair of elliptical galaxies, and NGC 5096, a compact system which appears to be interacting with NGC 5098. We aim to describe its current dynamical state in order to investigate how it fits in our current cosmological framework. Our analysis is based on deep Canada-France-Hawaii Telescope (CFHT/MegaCam) g and r imaging, archival Chandra X-ray data, and publicly available data of the galaxy redshift distribution. We model the surface brightness of the 12 brightest galaxies in the field-of-view and investigate the diffuse intragroup light that we detect. With a redshift sample of 112 galaxies, we study the dynamical states of both groups. We detect low surface brightness diffuse light associated with both galaxy-galaxy interactions and a possible group-group collision. The substructure we found in velocity space indicates a past interaction between both groups. This is further corroborated by the X-ray analysis. We conclude that NGC 5098 and NGC 5096 form a complex system, that may have collided in the past, producing a sloshing observed in X-rays and a large scale diffuse component of intragroup light as well as some important tidal debris.