NBODY/SPH simulations of individual galaxies

We present preliminary results on galactic Dark Matter (DM), halo structure, and galaxy evolution. We show how during the first Gyr of the evolution of a $10^{10} M_{\odot}$ dwarf elliptica feed-back from stars (SN\ae~ and stellar winds) leads to an extended constant density isothermal core with radius of 0.15 the virial radius $R_{200}$. We also present first results on galaxy merging as a possibile scenario to form ellipticals, studying in particular how the details of the merging evolution vary as a function of the mass ratio of the interacting galaxies.