Shape and kinematics of elliptical galaxies: evolution due to merging at z ${<}$ 1.5

Aims. We investigate the evolution in the shape and kinematics of elliptical galaxies in a cosmological framework. Methods. We identified relaxed, elliptical-like objects (ELOs) at redshifts $z = 0$, $z = 0.5$, $z = 1$ and $z = 1.5$ within a set of hydrodynamic, self-consistent simulations completed for a concordance cosmological model. Results. The population of elliptical systems that we analysed evolve systematically with time becoming rounder in general by $z = 0$ and also more velocity dispersion supported. We found that this is due primarily to major dry mergers where only a modest amount of angular momentum is involved in the merger event. Despite the general trend, in a significant number of cases the merger event involves a relatively high amount of specific angular momentum, which causes the system in general to acquire higher rotational support and/or a more oblate shape. These evolutionary patterns persist when we study our systems in projection, in simulating true observations, and thus should be evident in future observations.