http://arxiv.org/abs/1505.03656
Using N-body simulations, we measure the power spectrum of the effective dark matter density field, which is defined through the modified Poisson equation in $f(R)$ cosmologies. We find that when compared to the conventional dark matter power spectrum, the effective power spectrum deviates more significantly from the $\Lambda$CDM model. For models with $f_{R0}=-10^{-4}$, the deviation can exceed 150\% while the deviation of the conventional matter power spectrum is less than 50\%. Even for models with $f_{R0}=-10^{-6}$, for which the conventional matter power spectrum is very close to the $\Lambda$CDM prediction, the effective power spectrum shows sizeable deviations. Our results indicate that traditional analyses based on the dark matter density field may seriously underestimate the impact of $f(R)$ gravity on galaxy clustering. We therefore suggest the use of the effective density field in such studies.
J. He, B. Li and A. Hawken
Fri, 15 May 15
36/71
Comments: 11 pages, 9 figures
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