Decoding the stellar fossils of the dusty Milky Way progenitors

We investigate the metallicity distribution function (MDF) of the Galactic halo and the relative fraction of Carbon-normal and Carbon-rich stars using the semi-analytical code GAMETE. The code reconstructs the hierarchical merger tree of the Milky Way (MW) and follows the star formation history and the metal evolution in individual progenitors, including for the first time the formation and evolution of dust. We predict scaling relations between the dust, metal and gas masses for MW progenitors and compare them with observational data of galaxies at 0 ≤ z < 6.3. We find that the relative contribution of C-normal and C-enhanced stars to the MDF and its dependence on [Fe/H] allow to discriminate among different Pop III/II transition criteria as well as between different Initial Mass Functions (IMFs) and supernova (SN) yields for Population III stars.