Behavior of luminous matter in the head-on encounter of two ultralight BEC dark matter halos

Within the context of ultralight Bose-Einstein condensate (BEC) dark matter, we analyze the head-on encounters of two structures. These structures are made of a BEC component, which is a ground-state equilibrium solution of the Gross-Pitaevskii-Poisson (GPP) system, together with a component of luminous matter. The evolution of the condensate dark matter is carried out by solving the time-dependent GPP equations, whereas the luminous matter is modeled with particles interacting gravitationally on top of the BEC dark matter halos. We track the evolution of frontal encounters for various values of the collision velocity and analyze the high-velocity regime showing solitonic behavior of the BEC halos and that of slow velocities producing a single final structure. We measure the relative velocity of the dark matter with respect to the luminous matter after the encounters in the solitonic case and track the evolution of luminous matter in the case of merger.