We examine the rotation rates , sizes , and star formation ( SF ) efficiencies of a representative population of simulated disc galaxies extracted from the Galaxies-Intergalactic Medium Interaction Calculation ( gimic ) suite of cosmological hydrodynamic simulations .
These simulations include efficient , but energetically feasible supernova feedback , but have not been tuned in any way to produce ‘ realistic ’ disc galaxies .
Yet , they generate a large number of discs , without requiring extremely high resolution .
Over the wide galaxy stellar mass range , 9.0 \la \log _ { 10 } [ M _ { * } ( M _ { \odot } ) ] < 10.5 , the simulations reproduce the observed Tully-Fisher relation , the rotation curves of disc galaxies in bins of stellar mass , the mass-size relation of disc galaxies , the optical rotation to virial circular velocity ratio ( ‘ V _ { opt } / V _ { vir } ’ ) , and the SF efficiencies of disc galaxies as inferred from stacked weak lensing and stacked satellite kinematics observations .
They also reproduce the specific star formation rates of \sim L* galaxies but predict too low levels of star formation for low-mass galaxies , which is plausibly due to the finite resolution of the simulations .
At higher stellar masses , \log _ { 10 } [ M _ { * } ( M _ { \odot } ) ] > 10.6 , the simulated galaxies are too concentrated and have too high SF efficiencies .
We conjecture that this shortcoming reflects the neglect of feedback from accreting supermassive black holes in these simulations .
We conclude that it is possible to generate a representative population of disc galaxies that reproduces many of the observed trends of local disc galaxies using standard numerical hydrodynamic techniques and a plausible implementation of the “ subgrid ” astrophysical processes thought to be relevant to galaxy formation .