Hierarchical galaxy formation in the Local Group
Exploiting the Milky Way and its satellite galaxies as
laboratories to study galaxy formation and evolution
The scenario predicted by cosmological models for the formation of our Galaxy is that of hierarchical structure formation, where small units of matter, the "building blocks," gradually merged over time to form galaxies and their components. In recent years, significant progress has been made, thanks to Gaia and ground based spectroscopic surveys, in identifying the remnants of these building blocks that contributed to the formation of the Milky Way. HRMOS will open new possibilities, enabling the study, in equal detail, of the chemistry of stars in the Milky Way's closest companions, namely the Large and Small Magellanic Clouds and Sagittarius, and possibly identifying the building blocks of dwarf galaxies. This will allow a deeper understanding of the formation and evolution of the Galaxy, exploring the interactions between the Milky Way and its satellite galaxies. High spectral resolution is crucial here in order to precisely identify differences in chemical abundances, and to include key elements, which are not possible to measure at medium resolution, as in 4MOST or WEAVE.