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

Johnson, A.; Blake, Chris; Dossett, Jason; Koda, Jun; Parkinson, David; Joudaki, Shahab

doi:10.1093/mnras/stw447

Cited by 55 publications

(51 citation statements)

References 84 publications

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“…Dynamical probes include cluster counts (CC) [29][30][31][32], weak lensing (WL) [25,[33][34][35][36][37][38][39] and redshift-space distortions (RSD) [1,2,[40][41][42]. These probes are consistent with each other pointing either to a lower value of the matter density parameter Ω 0m in the context of GR or to weaker gravitational growth power than the growth indicated by GR in the context of a Planck18ΛCDM background geometry at about 2 − 3σ level [1,2,41].…”

Section: Introductionmentioning

confidence: 64%

Tension of the EG statistic and redshift space distortion data with the Planck - ΛCDM model and implications for weakening gravity

Skara

Perivolaropoulos

2020

Phys. Rev. D

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The EG statistic is a powerful probe for detecting deviations from GR by combining weak lensing (WL), real-space clustering and redshift space distortion (RSD) measurements thus probing both the lensing and the growth effective Newton constants (GL and G ef f ). We construct an up to date compilation of EG statistic data including both redshift and scale dependence (EG(R, z)). We combine this EG data compilation with an up to date compilation of f σ8 data from RSD observations to identify the current level of tension between the Planck/ΛCDM standard model based on general relativity and a general model independent redshift evolution parametrization of GL and G ef f . Each f σ8 datapoint considered has been published separately in the context of independent analyses of distinct galaxy samples. However, there are correlations among the datapoints considered due to overlap of the analyzed galaxy samples. Due to these correlations the derived levels of tension of the best fit parameters with Planck/ΛCDM are somewhat overestimated but this is the price to pay for maximizing the information encoded in the compilation considered. We find that the level of tension increases from about 3.5σ for the f σ8 data compilation alone to about 6σ when the EG data are also included in the analysis. The direction of the tension is the same as implied by the f σ8 RSD growth data alone (lower Ωm and/or weaker effective Newton constant at low redshifts for both the lensing and the growth effective Newton constants (GL and G ef f )). These results further amplify the hints for weakening modified gravity discussed in other recent analyses [1][2][3][4].

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Section: Introductionmentioning

confidence: 64%

Tension of the EG statistic and redshift space distortion data with the Planck - ΛCDM model and implications for weakening gravity

Skara

Perivolaropoulos

2020

Phys. Rev. D

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“…Daniel et al 2010;Johnson et al 2016;Ade et al 2016b;Di Valentino, Melchiorri & Silk 2016a). To this end, we use ISITGR (Dossett, Ishak & Moldenhauer 2011;Dossett & Ishak 2012), which is an integrated set of modified modules in COSMOMC designed to test gravity on cosmic scales.…”

Section: Modified Gravitymentioning

confidence: 99%

KiDS-450: testing extensions to the standard cosmological model

Joudaki

Mead

Blake

et al. 2017

Monthly Notices of the Royal Astronomical Society

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191

289

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We test extensions to the standard cosmological model with weak gravitational lensing tomography using 450 deg 2 of imaging data from the Kilo Degree Survey (KiDS). In these extended cosmologies, which include massive neutrinos, nonzero curvature, evolving dark energy, modified gravity, and running of the scalar spectral index, we also examine the discordance between KiDS and cosmic microwave background measurements from Planck. The discordance between the two datasets is largely unaffected by a more conservative treatment of the lensing systematics and the removal of angular scales most sensitive to nonlinear physics. The only extended cosmology that simultaneously alleviates the discordance with Planck and is at least moderately favored by the data includes evolving dark energy with a time-dependent equation of state (in the form of the w 0 − w a parameterization). In this model, the respective S 8 = σ 8 Ω m /0.3 constraints agree at the 1σ level, and there is 'substantial concordance' between the KiDS and Planck datasets when accounting for the full parameter space. Moreover, the Planck constraint on the Hubble constant is wider than in ΛCDM and in agreement with the Riess et al. (2016) direct measurement of H 0 . The dark energy model is moderately favored as compared to ΛCDM when combining the KiDS and Planck measurements, and remains moderately favored after including an informative prior on the Hubble constant. In both of these scenarios, marginalized constraints in the w 0 − w a plane are discrepant with a cosmological constant at the 3σ level. Moreover, KiDS constrains the sum of neutrino masses to 4.0 eV (95% CL), finds no preference for time or scale dependent modifications to the metric potentials, and is consistent with flatness and no running of the spectral index. The analysis code is publicly available at https://github.com/sjoudaki/kids450.

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“…[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.…”

Section: Introductionmentioning

confidence: 99%

Cosmological hints of modified gravity?

2016

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The recent measurements of Cosmic Microwave Background temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the ΛCDM cosmological model. However interesting hints of slight deviations from ΛCDM have been found, including a 95% c.l. preference for a "modified gravity" structure formation scenario. In this paper we confirm the preference for a modified gravity scenario from Planck 2015 data, find that modified gravity solves the so-called A lens anomaly in the CMB angular spectrum, and constrains the amplitude of matter density fluctuations to σ8 = 0.815 +0.032 −0.048 , in better agreement with weak lensing constraints. Moreover, we find a lower value for the reionization optical depth of τ = 0.059 ± 0.020 (to be compared with the value of τ = 0.079 ± 0.017 obtained in the standard scenario), more consistent with recent optical and UV data. We check the stability of this result by considering possible degeneracies with other parameters, including the neutrino effective number, the running of the spectral index and the amount of primordial helium. The indication for modified gravity is still present at about 95% c.l., and could become more significant if lower values of τ were to be further confirmed by future cosmological and astrophysical data. When the CMB lensing likelihood is included in the analysis the statistical significance for MG simply vanishes, indicating also the possibility of a systematic effect for this MG signal.

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

Cited by 55 publications

References 84 publications

Tension of the EG statistic and redshift space distortion data with the Planck - ΛCDM model and implications for weakening gravity

Tension of the EG statistic and redshift space distortion data with the Planck - ΛCDM model and implications for weakening gravity

KiDS-450: testing extensions to the standard cosmological model

Cosmological hints of modified gravity?

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