The UV window on counter rotating ETGs: insight from SPH simulations with chemo-photometric implementation

The UV images of the Galaxy Evolution Explorer satellite revealed that about (30\ub13)% of early-type galaxies show UV emission indicating a rejuvenation episode. In early-type galaxies with multi-spin components this percentage increases at 50%. We present here the characteristics of this sample and our smooth particle hydrodynamic simulations with chemo-photometric implementation that provide dynamical and morphological information together with the spectral energy distribution at each evolutionary stage. We show our match of the global properties of two early-type galaxies, NGC 3626 and NGC 5173. For these galaxies we can trace their evolutionary path