Extragalactic astronomical objects, like galaxies, cover a broad range of mechanisms responsible for powering the engines of the respective galaxies: e.g., ULIRGs (UltraLuminous Infrared Galaxies), a product of mergers between galaxies that are supposedly powered by starbursts, AGN or a mixture of the two, and QSOs (quasistellar objects) which are powered by AGN. Since ULIRGs and QSOs show similar properties (especially the infrared luminosities) it was proposed that they form the early and late phase of an evolutionary sequence where supposedly ULIRGs are the dust enshrouded progenitors of...