Turbulence-Dominated versus Thermal Energy-Dominated CGM: Implications for Galaxy Evolution

          @misc{ pirsa_PIRSA:25070021,
            doi = {10.48660/25070021},
            url = {https://pirsa.org/25070021},
            author = {Stern, Johnathan},
            keywords = {Cosmology},
            language = {en},
            title = {Turbulence-Dominated versus Thermal Energy-Dominated CGM: Implications for Galaxy Evolution},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {jul},
            note = {PIRSA:25070021 see, \url{https://pirsa.org}}
          }
          

Abstract

I will present evidence from both simulations and observations that the inner CGM (≲0.3 Rvir) of ≲L* galaxies departs significantly from the conventional paradigm of cool clouds embedded in a volume-filling hot phase. Instead, these regions are characterized by a supersonically turbulent medium in which kinetic energy dominates over thermal energy, with gas temperatures 10^4 –10^5 K and wide lognormal density distributions. I will show that UV absorption features observed at redshifts z ≲ 1, as well as DLAs at z ≳ 2, support this turbulence-dominated CGM framework. I will also discuss the broader implications of the transition from kinetic to thermal energy dominance for models of galaxy accretion, feedback processes, and the evolution from thick to thin star-forming disks.