Combining galaxy cluster and void abundances is a novel, powerful way to constrain deviations from General Relativity and the ΛCDM model. For a flat wCDM model with growth of large-scale structure parameterized by the redshift-dependent growth index γ(z)=γ0+γ1z/(1+z) of linear matter perturbations, combining void and cluster abundances in future surveys with Euclid and the 4-metre Multi-Object Spectroscopic Telescope (4MOST) could improve the Figure of Merit for (w,γ0,γ1) by a factor of 20 compared to individual abundances. In an ideal case, improvement on current cosmological data is a Figure of Merit factor 600 or more.
@article{arxiv.1612.06595,
title = {Cluster-Void Degeneracy Breaking: Modified Gravity in the Balance},
author = {Martin Sahlén and Joseph Silk},
journal= {arXiv preprint arXiv:1612.06595},
year = {2018}
}
Comments
9 pages, 3 figures, 4 tables. Matches published version. Added redshift-dependent growth index, significantly extended discussion on void sensitivity to cosmological parameters. Basic conclusions unchanged