The properties of the CGM and its relationship with galaxies in the COLIBRE simulations

          @misc{ pirsa_PIRSA:25070028,
            doi = {10.48660/25070028},
            url = {https://pirsa.org/25070028},
            author = {},
            keywords = {Cosmology},
            language = {en},
            title = {The properties of the CGM and its relationship with galaxies in the COLIBRE simulations},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {jul},
            note = {PIRSA:25070028 see, \url{https://pirsa.org}}
          }
          

Abstract

The upcoming COLIBRE project promises to provide a generational leap in the capabilities of cosmological, hydrodynamical simulations of galaxy formation. The simulations model the evolution of cold gas down to temperatures of 10 K, alongside the formation and evolution of dust, in large cosmological volumes, and incorporate new prescriptions for cooling, chemical enrichment, and feedback associated with star formation and black hole growth. COLIBRE’s flagship simulations have been run in much larger cosmological volumes, at a given resolution, than its predecessor (EAGLE), producing commensurately larger galaxy populations to study. In my talk I will present a census of baryons in the circumgalactic medium (CGM) for the flagship COLIBRE simulations, as a function of halo mass and gas phase, and present some initial comparisons with available observational data. I will discuss how the properties of the CGM are influenced by COLIBRE’s new prescriptions for feedback from star formation and AGN, and compare the importance of these feedback channels for different halo mass ranges. In turn, I will demonstrate how the properties of the CGM relate to the cold atomic and molecular gas reservoirs of galaxies, and how the effects of feedback on the CGM play a crucial role in future star formation activity and quenching. I will end by exploring why diversity exists in the properties of galaxies and their CGM in haloes of the same mass, by showing that galaxy-CGM ecosystems with different properties exhibit markedly different histories in terms of mass assembly, mergers, and feedback.