ABSTRACT
We utilize the public Gizmo code to simulate twelve galaxies from the NIHAO suite simulated with the ESF-Gasoline2 code, then compare the corresponding galaxies in the two simulations. We find that while both codes with the same initial conditions and large-scale environments can successfully produce similar disc galaxies, significant differences are still seen in many properties of the galaxies, particularly in the circumgalactic medium (CGM) environment they reside. Specifically, the thermal feedback recipe used in Gasoline results in ubiquitous long-lasting collimated outflows, primarily driven by high-density hot interstellar medium (ISM) from the galaxy center, and inflows of gas not aligned with the outflow cools rapidly and flows towards the galactic center. In contrast, galaxies from GIZMO do not exhibit large-scale outflows at low redshifts, but instead display quasi-virialized hot gaseous halos that arise from the strong interaction between inflow of gas and feedback driven outflow. The differences in the distribution of CGM gas are mainly due to different feedback models implemented in the two codes, thus future observations of CGM provide valuable insight into the physics governing the baryon cycle in disc galaxies. I will also showcase some intriguing findings from our recent hydro-simulations of merging disc galaxies.
