The clustering of galaxies in the completed SDSSIII Baryon Oscillation Spectroscopic Survey: constraining modified gravity
Abstract
We use baryon acoustic oscillation and redshift space distortion from the completed Baryon Oscillation Spectroscopic Survey, corresponding to Data Release 12 of the Sloan Digital Sky Survey, combined sample analysis in combination with cosmic microwave background, supernova, and redshift space distortion measurements from additional spectroscopic surveys to test deviations from general relativity. We present constraints on several phenomenological models of modified gravity: First, we parametrize the growth of structure using the growth index γ, finding γ = 0.566 ± 0.058 (68 per cent C.L.). Secondly, we modify the relation of the two Newtonian potentials by introducing two additional parameters, G_{M} and G_{L}. In this approach, G_{M} refers to modifications of the growth of structure whereas G_{L} to modification of the lensing potential. We consider a power law to model the redshift dependence of G_{M} and G_{L} as well as binning in redshift space, introducing four additional degrees of freedom, G_{M}(z < 0.5), G_{M}(z > 0.5), G_{L}(z < 0.5), and G_{L}(z > 0.5). At 68 per cent C.L., we measure G_{M} = 0.980 ± 0.096 and G_{L} = 1.082 ± 0.060 for a linear model, G_{M} = 1.01 ± 0.36 and G_{L} = 1.31 ± 0.19 for a cubic model as well as G_{M}(z < 0.5) = 1.26 ± 0.32, G_{M}(z > 0.5) = 0.986 ± 0.022, G_{L}(z < 0.5) = 1.067 ± 0.058, and G_{L}(z > 0.5) = 1.037 ± 0.029. Thirdly, we investigate general scalar tensor theories of gravity, finding the model to be mostly unconstrained by current data. Assuming a oneparameter f(R) model, we can constrain B_{0} < 7.7 × 10^{5} (95 per cent C.L). For all models we considered, we find good agreement with general relativity.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 April 2018
 DOI:
 10.1093/mnras/stx3232
 arXiv:
 arXiv:1612.00812
 Bibcode:
 2018MNRAS.475.2122M
 Keywords:

 gravitation;
 cosmological parameters;
 dark energy;
 largescale structure of Universe;
 cosmology: observations;
 cosmology: theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 10 pages, 7 figures, submitted to MNRAS