The growth and entrainment of cold gas in a hot wind

Understand

Both absorption and emission line studies show that cold gas around galaxies is commonly outflowing at speeds of several hundred km$\,\textrm{s}^{-1}$.

• This observational fact poses a severe challenge to our theoretical models of galaxy evolution since most feedback mechanisms (e.g., supernovae feedback) accelerate hot gas, and the timescale it takes to accelerate a blob of cold gas via a hot wind is much larger than the time it takes to destroy the blob.
• We revisit this long-standing problem using three-dimensional hydrodynamical simulations with radiative cooling.
• Our results confirm previous findings, that cooling is often not efficient enough to prevent the destruction of cold gas.