Role of extreme events in Galaxy evolution

ongoing

The primary goal of my proposal is to provide stringent observational constraints on the cosmic origins of elements heavier than iron and on the role of extreme objects in the evolution of the Milky Way. I will do this by employing abundances of different chemical elements for hundreds of thousands of stars from my high-resolution spectroscopic survey of the disk and bulge on the 4MOST instrument. These elements trace the production in a variety of extreme astrophysical sites: hydrostatic and explosive burning, s-process in asymptotic giant branch stars and in massive stars, r-process in compact binary mergers, neutrino-driven winds of core collapse supernovae, magnetars, and collapsars. I will use the novel Non-LTE models that I pioneered and successfully applied throughout my career to provide accurate and homogeneous chemical abundances of stars. I will quantify the trends of abundance ratios and their dispersions with metallicity, age, and location that will be directly compared with the predictions of Galactic chemical evolution models. My ERC project represents the first systematic investigation of s- and r-process nucleosynthesis in a large stellar sample. I will use the comprehensive maps of chemical enrichment to constrain the multimodality of the nuclear production sites, to confine the parameter space of stellar sources capable of hosting s- and r-process, and to test the role of these extreme events in the evolution of the Galaxy.