Abstract
We investigate the effect of the accelerated expansion of the Universe due to a cosmological constant, Lambda, on the cosmic star formation rate. We utilize hydrodynamical simulations from the EAGLE suite, comparing a Lambda CDM (cold dark matter) Universe to an Einstein-de Sitter model with Lambda = 0. Despite the differences in the rate of growth of structure, we find that dark energy, at its observed value, has negligible impact on star formation in the Universe. We study these effects beyond the present day by allowing the simulations to run forward into the future (t > 13.8 Gyr). We show that the impact of Lambda becomes significant only when the Universe has already produced most of its stellar mass, only decreasing the total comoving density of stars ever formed by approximate to 15 per cent. We develop a simple analytic model for the cosmic star formation rate that captures the suppression due to a cosmological constant. The main reason for the similarity between the models is that feedback from accreting black holes dramatically reduces the cosmic star formation at late times. Interestingly, simulations without feedback from accreting black holes predict an upturn in the cosmic star formation rate for t > 15 Gyr due to the rejuvenation of massive (> 10(11)M circle dot) galaxies. We briefly discuss the implication of the weak dependence of the cosmic star formation on in the context of the anthropic principle.
Original language | English |
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Pages (from-to) | 3744-3759 |
Number of pages | 16 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 477 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2018 |