Measuring gravity at cosmological scales

Abstract

This paper is a pedagogical introduction to models of gravity and how to constrain them through cosmological observations. We focus on the Horndeski scalar-tensor theory and on the quantities that can be measured with a minimum of assumptions. Alternatives or extensions of General Relativity have been proposed ever since its early years. Because of Lovelock theorem, modifying gravity in four dimensions typically means adding new degrees of freedom. The simplest way is to include a scalar field coupled to the curvature tensor terms. The most general way of doing so without incurring in the Ostrogradski instability is the Horndeski Lagrangian and its extensions. Testing gravity means therefore, in its simplest term, testing the Horndeski Lagrangian. Since local gravity experiments can always be evaded by assuming some screening mechanism or that baryons are decoupled, or even that the effects of modified gravity are visible only at early times, we need to test gravity with cosmological observations in the late universe (large-scale structure) and in the early universe (cosmic microwave background). In this work we review the basic tools to test gravity at cosmological scales, focusing on model-independent measurements.

Review paper. Clarified some aspects and added new references

References in corpus (39)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• A gravitational-wave standard siren measurement of the Hubble constant
• Covariant Galileon
• Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z$\sim$2
• Dark Energy after GW170817: dead ends and the road ahead
• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Strong constraints on cosmological gravity from GW170817 and GRB 170817A
• Dark Energy after GW170817 and GRB170817A
• Implications of the Neutron Star Merger GW170817 for Cosmological Scalar-Tensor Theories
• Healthy theories beyond Horndeski
• A test of the nature of cosmic acceleration using galaxy redshift distortions
• Horndeski theory and beyond: a review
• New Parallaxes of Galactic Cepheids from Spatially Scanning the Hubble Space Telescope: Implications for the Hubble Constant
• Primordial Nucleosynthesis: from precision cosmology to fundamental physics
• Exploring gravitational theories beyond Horndeski
• Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity
• A discriminating probe of gravity at cosmological scales
• Environmental Dependence of Masses and Coupling Constants
• Confirmation of general relativity on large scales from weak lensing and galaxy velocities
• Hubble Parameter and Baryon Acoustic Oscillation Measurement Constraints on the Hubble Constant, the Deviation from the Spatially-Flat $\Lambda$cdm Model, The Deceleration-Acceleration Transition Redshift, and Spatial Curvature
• The Clustering of the SDSS Main Galaxy Sample II: Mock galaxy catalogues and a measurement of the growth of structure from Redshift Space Distortions at $z=0.15$
• Type Ia Supernova Distances at z > 1.5 from the Hubble Space Telescope Multi-Cycle Treasury Programs: The Early Expansion Rate
• Anisotropic stress as signature of non-standard propagation of gravitational waves
• The gravitational-wave luminosity distance in modified gravity theories
• Generalized framework for testing gravity with gravitational-wave propagation. I. Formulation
• Observables and unobservables in dark energy cosmologies
• Clustering of luminous red galaxies I: large scale redshift space distortions
• The fate of large-scale structure in modified gravity after GW170817 and GRB170817A
• Primordial nucleosynthesis as a probe of fundamental physics parameters
• Cosmological Constraints on Horndeski Gravity in Light of GW170817
• Direct detection of gravitational waves can measure the time variation of the Planck mass
• Coupled quintessence with a $\Lambda$CDM background: removing the ${\sigma }_8$ tension
• No Slip Gravity
• Effects of modified gravity on B-mode polarization
• KiDS+2dFLenS+GAMA: Testing the cosmological model with the $E_{\mathrm{G}}$ statistic
• Cosmology with the Square Kilometre Array
• Doppelgänger dark energy: modified gravity with non-universal couplings after GW170817
• How can we tell whether dark energy is composed by multiple fields?
• Gravitational wave speed: Implications for models without a mass scale

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• Imaging Systematics and Clustering of DESI Main Targets
• Gravitational wave propagation in $f(R)$ models: New parametrizations and observational constraints
• $f(Q)$-gravity and neutrino physics
• New constraints on cosmological modified gravity theories from anisotropic three-point correlation functions of BOSS DR12 galaxies
• Comparison of different approaches to the quasi-static approximation in Horndeski models
• Gravitational Redshift Constraints on the Effective Theory of Interacting Dark Energy
• Probing Modified Gravity with Integrated Sachs-Wolfe CMB and Galaxy Cross-correlations
• MG-MAMPOSSt: A code to test modifications of gravity with the dynamics of galaxy clusters
• Quantum Cosmology of Fab Four John Theory with Conformable Fractional Derivative
• Constraining Horndeski theory with gravitational waves from coalescing binaries
• Large-scale asymmetry in galaxy spin directions: evidence from the Southern hemisphere
• Cosmological study of a symmetric teleparallel gravity model
• Model Independent Analysis of Supernova Data, Dark Energy, Trans-Planckian Censorship and the Swampland
• New evidence and analysis of cosmological-scale asymmetry in galaxy spin directions
• Testing gravity with the Milky Way: Yukawa potential
• Weak gravity on a $\Lambda$CDM background
• Testing the Equivalence Principle with Strong Lensing Time Delay Variations
• Analysis of $\sim 10^6$ spiral galaxies from four telescopes shows large-scale patterns of asymmetry in galaxy spin directions
• Testing modified gravity scenarios with direct peculiar velocities
• Non-linear Cosmological Perturbations for Coupled Dark Energy
• Large-scale asymmetry in galaxy spin directions -- analysis of galaxies with spectra in DES, SDSS, and DESI Legacy Survey
• Dark Universe inspired by the Kaluza-Klein gravity and impact on Primordial Gravitational Waves
• Signatures of modified gravity from the gravitational Aharonov-Bohm effect
• Transient weak gravity in scalar-tensor theories
• Velocity dispersion of dark matter deficient ultra-diffuse galaxies: A case for modified gravity
• Testing Screening Mechanisms with Mass Profiles of Galaxy Clusters
• Accelerated expansion as manifestation of gravity: when Dark Energy belongs to the left