Event Details

Understanding the properties of cold gas embedded in the hot halos around galaxies is a cornerstone in our theory of galaxy formation and evolution since it not only represents the fuel of future star-formation activity but also traces hot outflows which are hard to detect otherwise. In my talk, I will discuss the multiphase nature of this `circumgalactic medium’ (CGM), and some theoretical challenges associated with it. In particular, I want to focus on the characteristic length scale of the cold gas in phenomena such as galactic winds or thermal instability. As I will show, this scale has consequences for the survival and dynamics of cold gas, convergence criteria for large (cosmological) simulations, and the escape of resonant line photons such as Lyman-alpha. During my talk, I will show some analytical estimates and results from recent (magneto-) hydrodynamics simulations which suggest that the CGM can be in a “cloudy” or “misty” state.