The impact of the Universe's expansion rate on constraints on modified growth of structure

Abstract

In the context of modified gravity, at linear level, the growth of structure in the Universe will be affected by modifications to the Poisson equation and by the background expansion rate of the Universe. It has been shown that these two effects lead to a degeneracy which must be properly accounted for if one is to place reliable constraints on new forces on large scales or, equivalently, modifications to General Relativity. In this paper we show that current constraints are such that assumptions about the background expansion have little impact on constraints on modifications to gravity. We do so by considering the background of a $\Lambda$ Cold Dark Matter ($\Lambda$CDM) universe, a universe with a more general equation of state for the dark energy, and finally, a general, model-independent, expansion rate. We use Gaussian Processes to model modifications to Poisson's equation and, in the case of a general expansion rate, to model the redshift dependent Hubble rate. We identify a degeneracy between modifications to Poisson's equation and the background matter density, ${\Omega }_M$, which can only be broken by assuming a model-dependent expansion rate. We show that, with current data, the constraints on modifications to the Poisson equation via measurements of the growth rate range between $10-20\%$ depending on the strength of our assumptions on the Universe's expansion rate.

arXiv commentPrepared for submission to PRD. Comments welcome

References in corpus (48)

• Array Programming with NumPy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Modified Gravity and Cosmology
• Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• Baryonic Features in the Matter Transfer Function
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory
• Beyond the Cosmological Standard Model
• Constraining Cosmological Parameters Based on Relative Galaxy Ages
• The WiggleZ Dark Energy Survey: Joint measurements of the expansion and growth history at z < 1
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Overview and Early Data
• Tests of the Gravitational Inverse-Square Law
• The Reddening-Free Decline Rate Versus Luminosity Relationship for Type Ia Supernovae
• Cosmic Distances Calibrated to 1% Precision with Gaia EDR3 Parallaxes and Hubble Space Telescope Photometry of 75 Milky Way Cepheids Confirm Tension with LambdaCDM
• Cosmic Microwave Background Anisotropies
• The WiggleZ Dark Energy Survey: Survey Design and First Data Release
• The 6dF Galaxy Survey: z \approx 0 measurement of the growth rate and sigma_8
• Reconstruction of dark energy and expansion dynamics using Gaussian processes
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: BAO and RSD measurements from anisotropic clustering analysis of the Quasar Sample in configuration space between redshift 0.8 and 2.2
• A Review of automatic differentiation and its efficient implementation
• KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering
• DESI and other dark energy experiments in the era of neutrino mass measurements
• $H_0$ from cosmic chronometers and Type Ia supernovae, with Gaussian Processes and the novel Weighted Polynomial Regression method
• The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at $z\sim 1.4$
• Eppur è piatto? The cosmic chronometer take on spatial curvature and cosmic concordance
• The VIMOS Public Extragalactic Redshift Survey (VIPERS): The growth of structures at $0.5<z<1.2$ from redshift-space distortions in the clustering of the PDR-2 final sample
• Cosmological Tests of Gravity
• Model-independent reconstruction of $f(T)$ gravity from Gaussian Processes
• Quantifying the $S_8$ tension with the Redshift Space Distortion data set
• Determining Model-independent $H_0$ and Consistency Tests
• Measurements of $H_0$ and reconstruction of the dark energy properties from a model-independent joint analysis
• Falsifying $\Lambda$CDM: Model-independent tests of the concordance model with eBOSS DR14Q and Pantheon
• Phenomenology of dark energy: general features of large-scale perturbations
• Difficulties Distinguishing Dark Energy from Modified Gravity via Redshift Distortions
• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: constraining modified gravity
• The linear growth rate of structure in Parametrized Post Friedmannian Universes
• Gaussian processes reconstruction of dark energy from observational data
• Reconstruction of the Dark Energy equation of state from latest data: the impact of theoretical priors
• Model-independent cosmological constraints from growth and expansion
• Phenomenology of Large Scale Structure in scalar-tensor theories: joint prior covariance of $w_{\text{DE}}$, $\Sigma$ and $\mu$ in Horndeski
• Peculiar-velocity cosmology with Types Ia and II supernovae
• A Fast Route to Modified Gravitational Growth
• Machine Learning improved fits of the sound horizon at the baryon drag epoch
• Model-independent constraints on ${\Omega }_m$ and $H(z)$ from the link between geometry and growth
• Measurement on the cosmic curvature using the Gaussian process method
• Nested sampling with any prior you like

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