First results from SMAUG: The need for preventative stellar feedback and improved baryon cycling in semi-analytic models of galaxy formation

Understand

Semi-analytic models (SAMs) are a promising means of tracking the physical processes associated with galaxy formation, but many of their approximations have not been rigorously tested.

• As part of the SMAUG (Simulating Multiscale Astrophysics to Understand Galaxies) project, we compare predictions from the FIRE-2 hydrodynamical "zoom-in" simulations to those from the Santa Cruz SAM run on the same halo merger trees, with an emphasis on the global mass flow cycle.
• Our study includes 13 halos spanning low-mass dwarfs (M_vir~10^10 M_sun at z=0), intermediate-mass dwarfs (M_vir~10^11 M_sun) and Milky Way-mass galaxies (M_vir~10^12 M_sun).
• The SAM and FIRE-2 predictions agree relatively well with each other in terms of stellar and interstellar mass, but differ dramatically on circumgalactic mass (the SAM is lower than FIRE-2 by ~3 orders of magnitude for dwarfs).