Miao Li (Flatiron Institute, New York)
The Nature and Impact of Supernovae Feedback in Galaxy Formation
Circumgalactic Medium (CGM), where cosmic inflows interact with galactic outflows, bears critical information for galaxy formation. Current cosmological simulations can model cosmic inflows but their galactic outflows usually rely on ad hoc sub-grid models. The path forward requires better understanding the feedback physics and using physically-based models in large-scale simulations. In this talk, I will first summarize the recent progress of small-box hydrodynamical simulations focusing on the nature of supernovae (SNe) feedback; particularly, the hot outflows are much more powerful than cool outflows while also appearing very simple. Then, I will introduce our galactic scale simulations, which adopt the outflow models from the small-box simulations. For a Milky Way-mass galaxy, when the star formation surface density is low, hot outflows form large-scale fountains in the halo; when it is high, the outflows are bipolar in shape and can escape from the dark matter halo. I will discuss the resultant multiphase CGM from 10^4-7 K and how they compare to multi-wavelength observations. I will also discuss the implications to the missing baryon and the missing metals problems.