Stars, dust, and gas: evolution and impact of young star clusters in nearby galaxies in the era of JWST – STARCLUSTERS

The main objective of this project is to further our understanding of the evolution of galaxies through the study of young star clusters. These clusters offer us a direct view on recent star formation and provide us with key insights into the physical processes that govern stellar birth and determine the impact stellar feedback on the galactic environment.

To address this challenge we take advantage of our exceptional PHANGS-JWST Treasury Programs, which provides unprecedented insight into stellar populations and dust in nearby galaxies at high spatial resolution. Combined with existing PHANGS dataset from HST, VLT/MUSE and ALMA, we will obtain high quality spectro-photometric information for about 100,000 star clusters. To extract the physical information from these data, we will improve our spectro-photometric Bayesian modeling code CIGALE and combine it with an innovative machine learning approach based on Invertible Neural Networks (INNs). This will give us access to the full posterior distribution function, which is essential when studying multi-modal or degenerate problems, or when investigating complex correlations between many parameters. CIGALE will see the inclusion of new state-of-the-art models taking into account the stochastic sampling of the initial mass function, stellar binary evolution, young stellar objects, and the latest dust-emission models. Once fully trained on the CIGALE database the INN architecture will allow us to efficiently and reliably characterize all observed star clusters.

The combination of an exceptional dataset with advanced techniques will allow us to break the age-attenuation-metallicity degeneracies that plagued previous studies and tackle important open questions such as the relation between star clusters and the energetics of the interstellar medium, the relation between the age of stellar clusters and dust emission, how to trace star formation at different spatial scales, and the relation between star cluster properties and the environment they live in. We note that all data and software products generated during the course of this project will be made publicly available.

In summary, our main objectives are fourfold. First, our central aim is to shed new light on star formation and galaxy evolution through the study of young star clusters observed with JWST and other telescopes in a diverse set of nearby star-forming galaxies. To do so, our second aim is to develop and expand key software to model star clusters and extract information from spectro-photometric observations. These two objectives will be the foundation of our third aim, to train a new generation of young researchers both in astrophysics, but also more generally in skills that are widely applicable also outside of academia. Finally, our fourth aim is to substantially strengthen and expand the existing collaborative ties between the participating research groups in Germany and in France.