Journal Article

Semi-analytic galaxy formation in early dark energy cosmologies

Fabio Fontanot, Volker Springel, Raul E. Angulo and Bruno Henriques

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 426, issue 3, pages 2335-2341
Published in print November 2012 | ISSN: 0035-8711
Published online November 2012 | e-ISSN: 1365-2966 | DOI:
Semi-analytic galaxy formation in early dark energy cosmologies

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We study the impact of early dark energy (EDE) cosmologies on galaxy properties by coupling high-resolution numerical simulations with semi-analytic modelling (SAM) of galaxy formation and evolution. EDE models are characterized by a non-vanishing high-redshift contribution of dark energy, producing an earlier growth of structures and a modification of large-scale structure evolution. They can be viewed as typical representatives of non-standard dark energy models in which only the expansion history is modified, and hence the impact on galaxy formation is indirect. We show that in EDE cosmologies the predicted space density of galaxies is enhanced at all scales with respect to the standard Λ cold dark matter (ΛCDM) scenario, and the corresponding cosmic star formation history and stellar mass density are increased at high redshift. We compare these results with a set of theoretical predictions obtained with alternative SAMs applied to our reference ΛCDM simulation, yielding a rough measure of the systematic uncertainty of the models. We find that the modifications in galaxy properties induced by EDE cosmologies are of the same order of magnitude as intra-SAM variations for a standard ΛCDM realization (unless rather extreme EDE models are considered), suggesting that it is difficult to use such predictions alone to disentangle between different cosmological scenarios. However, when independent information on the underlying properties of host dark matter haloes is included, the SAM predictions on galaxy bias may provide important clues to the expansion history and the equation-of-state evolution.

Keywords: galaxies: evolution; galaxies: formation; cosmological parameters; cosmology: theory; early Universe

Journal Article.  4360 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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