Speaker
Description
Star formation is a key process that governs the baryon cycle within galaxies, but how it controls their growth remains elusive due to modeling uncertainties. To understand the impact of star formation models on galaxy evolution, we perform cosmological zoom-in radiation-hydrodynamic simulations of a dwarf dark matter halo with virial mass $M_{\rm vir} \sim 10^{10}\,M_\odot$ at $z=6$. Two different star formation models are compared, a multi-freefall model combined with a local gravo-thermo-turbulent condition, and a more self-consistent model based on a sink particle algorithm where gas accretion and star formation are directly controlled by the gas kinematics. We use cosmological zoom-in simulations with different spatial resolutions and find that star formation is more bursty in the runs with the sink algorithm, regulating star formation better than the gravo-thermo-turbulent model. The main reason for the increased burstiness is that the gas accretion rates onto the sinks are high enough to form stars on very short timescales, leading to more clustered star formation. As a result, the star-forming clumps are disrupted more quickly in the sink run due to more coherent radiation and supernova feedback. The overcooling feature is further mitigated when sink particles accrete the surrounding gas at the rate of inflowing mass flux than Bondi-Hoyle accretion scheme. Our results suggest that improving the modeling of star formation on small, sub-molecular cloud scales can significantly impact the global properties of simulated galaxies.
