AR 15797 (Archival Research)

Thu Jul 18 14:09:43 GMT 2024

Principal Investigator: Max Gronke
PI Institution: Max Planck Institute for Astrophysics
Investigators (xml)

Title: The Transport and Growth of Cold Gas from Galactic Winds into the Circumgalactic Medium
Cycle: 27

HST COS observations have unexpectedly discovered ubiquitous cold (T~10^4 K) gas around star forming galaxies. Its presence challenges current models of galaxy formation and evolution, which predict a galaxy halo to be filled with hot gas. The origins of this cold gas found in the circumgalactic medium (CGM) are debated. A different - but possibly related - problem concerns the cold gas found in hot galactic winds which is unexpected since hydrodynamical instabilities should destroy the cold gas on short timescales. We will address these two fundamental issues by building upon recent theoretical developments which show that (i) cold gas can be accelerated through ram pressure as mixed gas can reform in the tail of a cloud, and (ii) cold gas mass growth can proceed even once the cloud is comoving with the wind. This implies that potentially a large cold gas mass found in the CGM can be transported out by galactic winds. We will test the feasibility of this idea by combining the (hot) wind profile of the FIRE simulation with ultra-high resolution \`wind tunnel' simulations which allow us predict the final cold gas mass transported out into the CGM. We will generate SiII, OVI and other metal line profile which can be directly compared to HST observations. Key predictions are the mass loading rates for different gas phases, as well as line-widths and centroids for various transition lines.