Gravity at the horizon: on relativistic effects, CMB-LSS correlations and ultra-large scales in Horndeski's theory

Abstract

We address the impact of consistent modifications of gravity on the largest observable scales, focusing on relativistic effects in galaxy number counts and the cross-correlation between the matter large scale structure (LSS) distribution and the cosmic microwave background (CMB). Our analysis applies to a very broad class of general scalar-tensor theories encoded in the Horndeski Lagrangian and is fully consistent on linear scales, retaining the full dynamics of the scalar field and not assuming quasi-static evolution. As particular examples we consider self-accelerating Covariant Galileons, Brans-Dicke theory and parameterizations based on the effective field theory of dark energy, using the \hiclass\, code to address the impact of these models on relativistic corrections to LSS observables. We find that especially effects which involve integrals along the line of sight (lensing convergence, time delay and the integrated Sachs-Wolfe effect -- ISW) can be considerably modified, and even lead to $\mathcal{O}(1000\%)$ deviations from General Relativity in the case of the ISW effect for Galileon models, for which standard probes such as the growth function only vary by $\mathcal{O}(10\%)$. These effects become dominant when correlating galaxy number counts at different redshifts and can lead to $\sim 50\%$ deviations in the total signal that might be observable by future LSS surveys. Because of their integrated nature, these deep-redshift cross-correlations are sensitive to modifications of gravity even when probing eras much before dark energy domination. We further isolate the ISW effect using the cross-correlation between LSS and CMB temperature anisotropies and use current data to further constrain Horndeski models (abridged).

30 pages plus appendices, 9 figures. References added. Accepted for publication in JCAP

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Cited by in corpus (40)

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• Consistency tests of $\Lambda$CDM from the early integrated Sachs-Wolfe effect: Implications for early-time new physics and the Hubble tension
• Effective Field Theory of Dark Energy: a Review
• Speed of Gravitational Waves and the Fate of Scalar-Tensor Gravity
• Galileon Gravity in Light of ISW, CMB, BAO and $H_0$ data
• Dark Energy in light of Multi-Messenger Gravitational-Wave astronomy
• Effective Description of Higher-Order Scalar-Tensor Theories
• hi_class: Horndeski in the Cosmic Linear Anisotropy Solving System
• Generalized framework for testing gravity with gravitational-wave propagation. II. Constraints on Horndeski theory
• The Observational Future of Cosmological Scalar-Tensor Theories
• The Novel Probes Project -- Tests of Gravity on Astrophysical Scales
• Cosmological parameter constraints for Horndeski scalar-tensor gravity
• Cosmological Constraints on Horndeski Gravity in Light of GW170817
• hi_class: Background Evolution, Initial Conditions and Approximation Schemes
• The impact of relativistic effects on cosmological parameter estimation
• A comparison of Einstein-Boltzmann solvers for testing General Relativity
• Generalized framework for testing gravity with gravitational-wave propagation. III. Future prospect
• Challenges in Connecting Modified Gravity Theory and Observations
• Weakening Gravity on Redshift-Survey Scales with Kinetic Matter Mixing
• Parametrizing modified gravity for cosmological surveys
• Weak lensing by galaxy troughs with modified gravity
• Positivity bounds from multiple vacua and their cosmological consequences
• Lensing convergence in galaxy clustering in LambdaCDM and beyond
• K-mouflage Imprints on Cosmological Observables and Data Constraints
• Towards detection of relativistic effects in galaxy number counts using kSZ Tomography
• Measuring ISW with next-generation radio surveys
• Star-Galaxy Image Separation with Computationally Efficient Gaussian Process Classification
• Scalar-Tensor Gravity and DESI 2024 BAO data
• Horndeski gravity without screening in binary pulsars
• Radiative stability and observational constraints on dark energy and modified gravity
• CMB constraints on DHOST theories
• Generalized Brans-Dicke theories in light of evolving dark energy
• Cosmological effects of the Galileon term in Scalar-Tensor Theories
• Relativistic Corrections to the Growth of Structure in Modified Gravity
• Fully relativistic predictions in Horndeski gravity from standard Newtonian N-body simulations
• Relativistic effects in the large-scale structure with effective dark energy fluids
• The effective field theory of dark energy diagnostic of linear Horndeski theories after GW170817 and GRB170817A
• Cosmic variance mitigation in measurements of the integrated Sachs-Wolfe effect
• $G_3$ -- interacting scalar tensor dark energy
• Probing beyond-Horndeski gravity on ultra-large scales