Parallel sessions

Galaxy clusters represent the end result of a complex hierarchical structure formation, which, in the LCDM model of the Universe, is largely driven by the distribution of dark matter. As the latest stage of this evolution, they carry the peculiar imprint of the past physical processes that lead to their formation, which makes them unique laboratories to study dark matter, baryonic processes and their interactions. Our current understanding of clusters have shown some remarkable laws governing their properties, such as self-similarity, the size-mass relation or stellar-to-halo mass relation for galaxies. However, our theories still face a number of tensions such as the core-cusp or missing satellites problems. Several solutions are proposed to resolve these tensions, in particular taking into account the impact of internal and environmental baryonic processes, or considering alternative types of dark matter. Theories, simulations, and observations are moving forward together to explore and constrain new parameter spaces describing structure formation. On the observational side, current facilities (e.g. HST, Chandra, or NIKA2) and large surveys (DES, KIDS, HSC, DESI, PFS, ACT et SPT) are deepening our understanding of cluster physics, and painting a detailed picture of the dark matter and baryonic mechanisms at play. Jointly, numerical simulations are able to confront our understanding of the physical processes happening at various scales in clusters, and can suggest different scenarios to explore.This session aims to bring together observations, theories and simulations using clusters and its components to discuss recent progress in our understanding of dark matter, baryons and their interactions.