Constraints and tensions in testing general relativity from Planck and CFHTLenS data including intrinsic alignment systematics

Abstract

We present constraints on testing general relativity (GR) at cosmological scales using recent data sets and assess the impact of galaxy intrinsic alignment in the CFHTLenS lensing data on those constraints. We consider data from Planck temperature anisotropies, the galaxy power spectrum from the WiggleZ survey, weak-lensing tomography shear-shear cross-correlations from the CFHTLenS survey, integrated Sachs Wolfe-galaxy cross-correlations, and baryon acoustic oscillation data. We use three different parametrizations of modified gravity (MG), one that is binned in redshift and scale, a parametrization that evolves monotonically in scale but is binned in redshift, and a functional parametrization that evolves only in redshift. We present the results in terms of the MG parameters Q and Σ. We employ an intrinsic alignment model with an amplitude A CFHTLenS that is included in the parameter analysis. We find an improvement in the constraints on the MG parameters corresponding to a 40-53% increase on the figure of merit compared to previous studies, and GR is found consistent with the data at the 95% confidence level. The bounds found on A CFHTLenS are sensitive to the MG parametrization used, and the correlations between A CFHTLenS and MG parameters are found to be weak to moderate. For all three MG parametrizations A CFHTLenS is found to be consistent with zero when the whole lensing sample is used; however, when using the optimized early-type galaxy sample a significantly nonzero A CFHTLenS is found for GR and the scaleindependent MG parametrization. We find that the tensions observed in previous studies persist, and there is an indication that cosmic microwave background (CMB) data and lensing data prefer different values for MG parameters, particularly for the parameter Σ. The analysis of the confidence contours and probability distributions suggest that the bimodality found follows that of the known tension in the σ 8 parameter.

SKA weak lensing – I. Cosmological forecasts and the power of radio-optical cross-correlations

“…We also consider modifications to gravity as parametrised in Dossett et al (2011Dossett et al ( , 2015. In General Relativity, from the perturbed Friedmann-Lemaitre-Robertson-Walker (FLRW) metric in the conformal Newtonian gauge:…”

“…For a given set of cosmological parameters ϑ we calculate a non-linear matter power spectrum using CAMB (Lewis et al 2000) (with modifications from ISiTGR for the modified gravity models from Dossett et al 2011Dossett et al , 2015 and halofit (Smith et al 2003;Takahashi et al 2012). This is then converted to a shear power spectrum using Eq.…”

Searching for modified gravity: scale and redshift dependent constraints from galaxy peculiar velocities

“…• Simpson et al (2013) measure the parameters {Σ, µ} (i.e., {G light , Gmatter}) using tomographic weak lensing measurements from CFHTLenS and RSD measurements of f σ8 from 6dFGS and WiggleZ, in addition to WMAP7 (including lowl) and geometric information (see also Dossett et al (2015) and Zhao et al (2012)). Their measurements are consistent with GR: they find µ = 1.05 ± 0.25 and Σ = 1.00 ± 0.14.…”

Cosmological hints of modified gravity?

“…The discrepancy with GR increases when weak lensing data is included, bringing the constrained value to Σ 0 − 1 = 0.34 +0. 17 −0.14 (again, see [3]). This result is clearly interesting and should be further investigated.…”

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]) have constrained possible deviations of the evolution of perturbations with respect to the ΛCDM model, by parametrizing the gravitational potentials Φ and Ψ and their linear combinations. Considering the parameter Σ, that modifies the lensing/Weyl potential given by the sum of the Newtonian and curvature potentials Ψ + Φ, the analysis of [3] reported the current value of Σ 0 − 1 = 0.28 ± 0.15 at 68% from Planck CMB temperature data, i.e.…”