How galaxies form and evolve is one of the main open questions in astrophysics. Using the Milky Way (MW) and nearby dwarf galaxies as a laboratory for galaxy evolution has the advantage of accessing individual elemental abundance measurements in stars, which allows the study of galaxy's chemical evolution in detail.
It is widely accepted in the literature that a significant portion of the stars in the MW originated in other galaxies and were subsequently accreted by our own. However, overlaps in the chemical space of various accreted substructures were observed, making it challenging to trace their origins. Disentangling these stars into their distinct progenitor populations and fully characterizing the dwarf galaxies they originated from is essential to understanding the MW's assembly history. Additionally, characterizing nearby dwarf galaxies may provide valuable insights into galaxy formation and evolution in general, as they have an overall simpler chemical evolutionary history than the MW, and are typically old and metal-poor, making them an excellent laboratory to study the first stars.
However, given the complexity of the Milky Way and the current limited data available for individual stars in nearby dwarf galaxies, chemical evolution models are essential for building a more complete understanding of both the progenitor galaxies of accreted stars in the MW and nearby dwarf galaxies. By comparing data from both accreted stars in the Galaxy and stars in dwarf galaxies with chemical evolution models, it will be possible to: I) more effectively disentangle accreted stellar populations in the Milky Way, identifying which substructures originated from independent progenitors, and II) infer crucial information on the evolution of nearby dwarf galaxies (e.g. star formation timescales and efficiency, the impact of different nucleosynthetic channels in the chemical enrichment of the galaxies).
In this project, the Versatile Integrator for Chemical Evolution (VICE; Johnson et al. 2021, Johnson et al. 2022) will be used to develop chemical evolution models of dwarf galaxies. VICE tracks 77 chemical elements from the periodic table and provides flexible nucleosynthetic yield calculations. Leveraging VICE's flexibility, we will construct chemical evolution models for dwarf galaxies using various star formation histories, nucleosynthetic yields, and evolutionary paths. This will result in a comprehensive library of models covering dwarf galaxies across a broad spectrum of masses and evolutionary trajectories. The models will be compared with data available from spectroscopic surveys such as APOGEE (Abolfathi et al. 2018) and GALAH (Buder et al. 2020), as well as literature data (e.g. Chitti et al. 2018, Skúladóttir et al. 2019, de Brito Silva et al. 2024). This project will directly support the 4MOST survey, which several Swedish institutions have heavily invested in, by providing chemical evolution models that will aid in interpreting the extensive data generated by the survey. 4MOST will propel the study of metal-poor stars and dwarf galaxies, by expanding the number of such stars with currently available chemical abundance data by a factor of 100.