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arXiv · 1612.06595

Cluster-Void Degeneracy Breaking: Modified Gravity in the Balance

Martin Sahlén·Joseph Silk
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Abstract

Combining galaxy cluster and void abundances is a novel, powerful way to constrain deviations from General Relativity and the $\Lambda$CDM model. For a flat $w$CDM model with growth of large-scale structure parameterized by the redshift-dependent growth index $\gamma(z) = \gamma_0 + \gamma_1 z/(1+z)$ 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 ($w, \gamma_0, \gamma_1$) 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.

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Martin Sahlén, Joseph Silk. 2016-12-20. Cluster-Void Degeneracy Breaking: Modified Gravity in the Balance. https://doi.org/10.1103/physrevd.97.103504

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