Tracing the nature of dark energy with galaxy distribution |
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| Authors: | P Solevi R Mainini S A Bonometto A V Macciò A Klypin S Gottlöber |
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| Institution: | Physics Department G. Occhialini, Universitàdegli Studi di Milano–Bicocca, Piazza della Scienza 3, I20126 Milano, Italy;INFN, Via Celoria 16, I20133, Milano, Italy;Institute for Theoretical Physics, University of Zürich, Winterturstrasse 190, CH–8057 Zürich, Switzerland;Astronomy Department, New Mexico State University, Box 30001, Department 4500, Las Cruces, NM 88003-0001, USA;Astrophysikalisches Institut Potsdam, An der Sternwarte 16,14482 Potsdam, Germany |
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| Abstract: | Dynamical dark energy (DE) is a viable alternative to the cosmological constant. Constructing tests to discriminate between Λ and dynamical DE models is difficult, however, because the differences are not large. In this paper we explore tests based on the galaxy mass function, the void probability function (VPF), and the number of galaxy clusters. At high z , the number density of clusters shows large differences between DE models, but geometrical factors reduce the differences substantially. We find that detecting a model dependence in the cluster redshift distribution is a significant challenge. We show that the galaxy redshift distribution is potentially a more sensitive characteristic. We do this by populating dark matter haloes in N -body simulations with galaxies using well-tested halo occupation distributions. We also estimate the VPF and find that samples with the same angular surface density of galaxies, in different models, exhibition almost model-independent VPF which therefore cannot be used as a test for DE. Once again, geometry and cosmic evolution compensate each other. By comparing VPFs for samples with fixed galaxy mass limits, we find measurable differences. |
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| Keywords: | methods: analytical methods: numerical galaxies: clusters: general cosmology: theory |
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