Numerical simulations of interacting galaxies: Bar morphology

Abstract

We present several numerical simulations of the collision of two spiral galaxies. A spiral galaxy is modelled with a spherical bulge and halo and a Freeman disc. The bulge is composed of a collisionless collection of stars; the halo is composed of a set of collisionless particles of unknown nature, we only need to know their gravitational influence and that the halo particles do not collide among them; and the disc is composed of stars only, gas or dust are not considered in this work. A bar is usually formed due to tidal effects after the first encounter of the spirals and we have found that this was the case in all the numerical experiments we did. The bar morphology is then studied during the evolution of the collision process. Here the morphology is the bar formation in the spiral discs, its geometry, i.e., minor and major axis length; and also we show how one of the collision galaxy partners change its disc geometry due to impact of the other galaxy. We show finally how the morphology of spiral galaxies changes due to collision geometrical parameters: impact parameter or the angle between symmetry axes of the spiral discs.