Merging of Elliptical Galaxies as Possible Origin of the Intergalactic Stellar Population

We present N-body simulations of elliptical galaxy encounters into dry mergers to study the resulting unbound intergalactic stellar population, in particular that of the post-Main Sequence stars. The systems studied are pairs of spherical galaxies without dark halos. The stellar content of the model galaxies is distributed into mass-bins representing lowand intermediate-mass stars (0.85 – 8 M⊙) according to Salpeter’s initial mass function. Our models follow the dynamical evolution of galaxy encounters colliding head-on from initial low-energy parabolic or high-energy mildly-hyperbolic orbits, and for a choice of initial-mass ratios. The merging models with initial parabolic orbits have M2/M1=1 and 10, and they leave behind respectively 5.5% and 10% of the total initial mass as unbound stellar mass. The merging model with initial hyperbolic orbit has M2/M1=1, and leaves behind 21% of its initial stellar mass as unbound mass, showing that the efficiency in producing intergalactic stars through a high-energy