A Numerical Experiment of a Triple Merger of Spirals

Abstract

We present a preliminary report on the dynamical evolution of triplets of spiral galaxies that lead to merger remnants that resemble an elliptical. We find that large projected stellar tidal tails ~200 Kpc can develop during the binary formation, and up to ~350 Kpc in the third galaxy when this merges with the binary. When gas is treated as test-particles, gaseous tidal tails may reach up to ~ 1 Mpc in radius in a Hubble time; this radius is similar to the size of the common dark halo formed during the interaction. It is suggested that gaseous tails may provide a mean to determine to some extent the size of the common dark halo formed during the merging of spirals. The stellar remnant shows an elliptical-like surface density profile, but its phase-space retains more information that can be used to determine whether it was assembled from spirals or not.