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The impact of dark energy on galaxy formation. What does the future of our Universe hold?

Salcido, J, Bower, RG, Barnes, LA, Lewis, GF, Elahi, PJ, Theuns, T, Schaller, M, Crain, RA and Schaye, J (2018) The impact of dark energy on galaxy formation. What does the future of our Universe hold? Monthly Notices of the Royal Astronomical Society, 477 (3). pp. 3744-3759. ISSN 0035-8711

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Abstract

We investigate the effect of the accelerated expansion of the Universe due to a cosmological constant, Λ, on the cosmic star formation rate. We utilize hydrodynamical simulations from the EAGLE suite, comparing a ΛCDM (cold dark matter) Universe to an Einstein–de Sitter model with Λ = 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 Λ 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 ≈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 (>1011 M⊙) galaxies. We briefly discuss the implication of the weak dependence of the cosmic star formation on Λ in the context of the anthropic principle.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astro-ph.CO; astro-ph.CO
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 05 Jun 2018 11:10
Last Modified: 22 Sep 2018 07:20
DOI or Identification number: 10.1093/mnras/sty879
URI: http://researchonline.ljmu.ac.uk/id/eprint/8774

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