Ian G. McCarthy, Joop Schaye, Andreea S. Font, Tom Theuns, Carlos S. Frenk, Robert A. Crain, Claudio Dalla Vecchia
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 < log10[Mstar (Msun)] < 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, and the SF efficiencies of disc galaxies as inferred from stacked weak lensing and stacked satellite kinematics observations. At higher stellar masses, log10[Mstar (Msun)] > 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 realistic and representative population of disc galaxies using standard numerical hydrodynamic techniques and a plausible implementation of the "subgrid" astrophysical processes thought to be relevant to galaxy formation.
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http://arxiv.org/abs/1204.5195
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