Constraining models of<i>f</i>(<i>R</i>) gravity with Planck and WiggleZ power spectrum data

Dossett, Jason; Hu, Bambi; Parkinson, David

doi:10.1088/1475-7516/2014/03/046

Cited by 76 publications

(90 citation statements)

References 151 publications

(222 reference statements)

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“…For this reason when lensing is added in Mock-C, the tension in A L , that for the lensing data set is smaller, pushes the posterior of B 0 toward smaller values, making it closer to GR. A similar effect was also observed for the Planck-2015 data set [26] and in the Planck-2013 data [27][28][29][30].…”

Section: Resultssupporting

confidence: 81%

Can modified gravity models reconcile the tension between the CMB anisotropy and lensing maps in Planck-like observations?

Raveri

2015

Phys. Rev. D

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Planck-2015 data seem to favour a large value of the lensing amplitude parameter, AL = 1.22 ± 0.10, in CMB spectra. This result is in 2σ tension with the lensing reconstruction result, A φφ L = 0.95 ± 0.04. In this paper, we simulate several CMB anisotropy and CMB lensing spectra based on Planck-2015 best-fit cosmological parameter values and Planck blue book beam and noise specifications. We analyse several modified gravity models within the effective field theory framework against these simulations and find that models whose effective Newton constant is enhanced can modulate the CMB anisotropy spectra in a way similar to that of the AL parameter. However, in order to lens the CMB anisotropies sufficiently, like in the Planck-2015 results, the growth of matter perturbations is substantially enhanced and gives a high σ8 value. This in turn proves to be problematic when combining these data to other probes, like weak lensing from CFHTLenS, that favour a smaller amplitude of matter fluctuations.

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Section: Resultssupporting

confidence: 81%

Can modified gravity models reconcile the tension between the CMB anisotropy and lensing maps in Planck-like observations?

Raveri

2015

Phys. Rev. D

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“…Similarly strong constraints can be obtained from the absence of deviations in luminosity distances from different types of distance indicators in unscreened dwarf galaxies [24]. Current cosmological constraints are about 2 orders of magnitude weaker than Solar System bounds [25][26][27]. We refer to Ref.…”

Section: Fig 1: Leftmentioning

confidence: 98%

Unscreening Modified Gravity in the Matter Power Spectrum

2015

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Viable modifications of gravity that may produce cosmic acceleration need to be screened in high-density regions such as the Solar System, where general relativity is well tested. Screening mechanisms also prevent strong anomalies in the large-scale structure and limit the constraints that can be inferred on these gravity models from cosmology. We find that by suppressing the contribution of the screened high-density regions in the matter power spectrum, allowing a greater contribution of unscreened low densities, modified gravity models can be more readily discriminated from the concordance cosmology. Moreover, by variation of density thresholds, degeneracies with other effects may be dealt with more adequately. Specializing to chameleon gravity as a worked example for screening in modified gravity, employing N -body simulations of f (R) models and the halo model of chameleon theories, we demonstrate the effectiveness of this method. We find that a percent-level measurement of the clipped power at k < 0.3 h/Mpc can yield constraints on chameleon models that are more stringent than what is inferred from Solar System tests or distance indicators in unscreened dwarf galaxies. Finally, we verify that our method is also applicable to the Vainshtein mechanism.Introduction.-Determining the nature of the accelerated expansion of our Universe is a prime endeavor to cosmologists. In the conventional picture, the flat Λ cold dark matter (ΛCDM) concordance model based on general relativity (GR), a cosmological constant Λ contributes the bulk of the present energy density in the cosmos and drives the late-time acceleration. While alternatively, a modification of gravity may be responsible for cosmic acceleration, stringent limitations from experiments within our Solar System must be satisfied. A number of screening mechanisms [1-5] have been identified that can suppress modifications of gravity in high-density regions to recover GR, while still generating significant modifications within lower densities on larger, cosmological scales. However, this suppression effect, along with other nonlinear effects, also prevents strong anomalies from manifesting in the averaged large-scale structure of our Universe [6] and limits the constraints that can be inferred on these gravity models from cosmology.Given the density dependence of the screening effect, in this Letter, we propose the downweighting of highdensity regions in statistical observables such as the matter power spectrum P (k) to enhance, or unscreen, the signatures of modified gravity and improve observational constraints. Such a weighting is conducted in the clipping method of Ref. [7], with the original motivation of facilitating the modeling of P (k) by reducing contributions of high densities, where the assumptions of perturbation theory break down. As a worked example, we first focus on Hu-Sawicki [8] f (R) gravity [9], which employs the chameleon screening mechanism [2]. We analyze effects on the power spectrum from clipping density fields in numerical simulations ...

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“…(16) provides an accurate way of modeling the kSZ spectrum in the fðRÞ models under consideration, allowing one to explore the parameter space in a much faster way. Let us notice that the fitting parameters in (17), and possibly the optimal fitting curve, may change if a different range of values for jf 0 R j is considered.…”

Section: Fitting Formulamentioning

confidence: 99%

“…In particular, viable fðRÞ models have been constrained with secondary CMB anisotropies, such as CMB lensing, the integrated Sachs-Wolfe effect [7,8] and its cross-correlation with galaxy density [9,10], galaxy cluster abundances [11][12][13] and profiles [14,15], galaxy power spectrum [16,17], redshift-space distortions from spectroscopic surveys [18][19][20], weak gravitational lensing [21,22], 21-cm intensity mapping [23], and dwarf galaxies [24,25].…”

Section: Introductionmentioning

confidence: 99%

Kinetic Sunyaev-Zel’dovich effect in modified gravity

Bianchini

Silvestri

2016

Phys. Rev. D

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We investigate the impact of modified theories of gravity on the kinetic Sunyaev-Zel'dovich (kSZ) effect of the cosmic microwave background. We focus on a specific class of fðRÞ models of gravity and compare their predictions for the kSZ power spectrum to that of the ΛCDM model. We use a publicly available modified version of Halofit to properly include the nonlinear matter power spectrum of fðRÞ in the modeling of the kSZ signal. We find that the well-known modifications of the growth rate of structure in fðRÞ can indeed induce sizable changes in the kSZ signal, which are more significant than the changes induced by modifications of the expansion history. We discuss prospects of using the kSZ signal as a complementary probe of modified gravity, giving an overview of assumptions and possible caveats in the modeling.

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Constraining models off(R) gravity with Planck and WiggleZ power spectrum data

Cited by 76 publications

References 151 publications

Can modified gravity models reconcile the tension between the CMB anisotropy and lensing maps in Planck-like observations?

Can modified gravity models reconcile the tension between the CMB anisotropy and lensing maps in Planck-like observations?

Unscreening Modified Gravity in the Matter Power Spectrum

Kinetic Sunyaev-Zel’dovich effect in modified gravity

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