2021/09/30 by Jessica M. Hislop, Thorsten Naab, Ulrich P. Steinwandel +4 · 1 citation
Physics and Astronomy · #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stab3347
17 pages, 13 figures. Accepted to be published in MNRAS. Comments welcome
arxiv created 2021/11/16 · arxiv updated 2021/12/22
We present results on the star cluster properties from a series of high resolution smoothed particles hydrodynamics (SPH) simulations of isolated dwarf galaxies as part of the GRIFFIN project. The simulations at sub-parsec spatial resolution and a minimum particle mass of 4 M_\odot incorporate non-equilibrium heating, cooling and chemistry processes, and realise individual massive stars. All the simulations follow feedback channels of massive stars that include the interstellar-radiation field, that is variable in space and time, the radiation input by photo-ionisation and supernova explosions. Varying the star formation efficiency per free-fall time in the range εff = 0.2 - 50% neither changes the star formation rates nor the outflow rates. While the environmental densities at star formation change significantly with εff, the ambient densities of supernovae are independent of εff indicating a decoupling of the two processes. At low εff, more massive, and increasingly more bound star clusters are formed, which are typically not destroyed. With increasing εff there is a trend for shallower cluster mass functions and the cluster formation efficiency Γ for young bound clusters decreases from 50 % to ∼ 1 % showing evidence for cluster disruption. However, none of our simulations form low mass (< 103 M_\odot) clusters with structural properties in perfect agreement with observations. Traditional star formation models used in galaxy formation simulations based on local free-fall times might therefore not be able to capture low mass star cluster properties without significant fine-tuning.