Observational Tests of Modified Gravity

By B. Jain, Pengjie Zhang. 2007

233 citations recorded by the source corpus.

Modifications of general relativity provide an alternative explanation to dark energy for the observed acceleration of the Universe. Modified gravity theories have richer observational consequences for large-scale structures than conventional dark energy models, in that different observables are not described by a single growth factor even in the linear regime. We examine the relationships between perturbations in the metric potentials, density and velocity fields, and discuss strategies for measuring them using gravitational lensing, galaxy cluster abundances, galaxy clustering/dynamics, and the integrated Sachs-Wolfe effect. We show how a broad class of gravity theories can be tested by combining these probes. A robust way to interpret observations is by constraining two key functions: the ratio of the two metric potentials, and the ratio of the gravitational "constant" in the Poisson equation to Newton's constant. We also discuss quasilinear effects that carry signatures of gravity, such as through induced three-point correlations. Clustering of dark energy can mimic features of modified gravity theories and thus confuse the search for distinct signatures of such theories. It can produce pressure perturbations and anisotropic stresses, which break the equality between the two metric potentials even in general relativity. With these two extra degrees of freedom, can a clustered dark energy model mimic modified gravity models in all observational tests? We show with specific examples that observational constraints on both the metric potentials and density perturbations can in principle distinguish modifications of gravity from dark energy models. We compare our result with other recent studies that have slightly different assumptions (and apparently contradictory conclusions).

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c55a828da2bd152bc81350facb95c1e320be7510

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In Astronomy and Astrophysics

Citations in the corpus

SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: COSMOLOGICAL INTERPRETATION (2010, background): “…al. 2007; Yamamoto et al. 2007; Chiba & Takahashi 2007; Bean et al. 2007; Hu & Sawicki 2007; Song et al. 2007; Starobinsky 2007; Daniel et al. 2008; Jain & Zhang 2008; Bertschinger & Zukin 2008; Amin et al. 2008; Hu 2008) and determine the mass of neutrinos (Hu et al. 1998; Lesgourgues & Pastor…”
f(R) Theories (2010, background): “Since the evolution of matter perturbations and gravitational potentials is different from that of GR, the observations of weak lensing can provide us an important test for probing modified gravity on galactic scales (see [2, 527, 27, 595, 528, 548] for theoretical aspects and [546, 348, 322, 3, 629”
The Kilo-Degree Survey (2012, background): “As noted above, the expansion history can be deduced from lensing tomography in several ways, and requiring consistency is a powerful check—as well as, further down the line, an interesting test of Einstein gravity theory [13].”
Beyond the Cosmological Standard Model (2014, unknown): “We follow the treatment of Jain & Zhang [906].”
Observational probes of cosmic acceleration (2012, background): “Relative to expectations for a cosmological constant or a simple scalar field model, models in which dark matter decays into dark energy can produce a mismatch between the histories of expansion and structure growth while maintaining GR (e.g., Jain and Zhang 2008; Wei and Zhang 2008).”
KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering (2017, background): “This is achieved by probing the relationship between the gravitational potentials ψ and φ describing temporal and spatial perturbations to the spacetime metric, respectively (e.g. Zhang et al. 2007; Jain & Zhang 2008; Guzik, Jain & Takada 2010; Song et al. 2011).”
Towards an accurate model of the redshift-space clustering of haloes in the quasi-linear regime (2011, background): “E-mail: beth.ann.reid@gmail.com both probe dark energy and test General Relativity (see e.g. Jain & Zhang 2008; Nesseris & Perivolaropoulos 2008; Song & Koyama 2009; Song & Percival 2009; Percival & White 2008; McDonald & Seljak 2008; White, Song & Percival 2009, for recent studies).”
KiDS-450: testing extensions to the standard cosmological model (2016, background): “…in the conformal Newtonian gauge, ρ i is the density of species i, G is Newton’s gravitational constant and Q(k, a) encodes the time and scale-dependent modifications to the Poisson equation (e.g. Jain & Zhang 2008; Bean & Tangmatitham 2010; Dossett et al. 2015, also see Ma & Bertschinger 1995).”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measurements of the growth of structure and expansion rate at z = 0.57 from anisotropic clustering (2012, background): “…the motions of galaxies carry an imprint of the rate of growth of large-scale structure and allow us to both probe dark energy and test GR (see e.g. Jain & Zhang 2008; Neseris & Perivolaropoulos 2008; Percival & White 2008; Song & Koyama 2009; Song & Percival 2009; McDonald & Seljak 2009; White,…”
LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, background): “…and cluster counting), LSST data can reveal whether the recent cosmic acceleration is due to dark energy or modified gravity (Lue, Scoccimarro & Starkman 2004; Knox, Song & Tyson 2006; Ishak, Upadhye & Spergel 2006; Jain & Zhang 2008; Oguri & Takada 2011; Jain et al. 2013; Weinberg et al. 2013).”
Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018: Technical specifications and performance forecasts (2018, background): “The growth rate in particular is valuable for testing alternative theories of gravity, which tend to enhance or suppress galaxy peculiar velocities with respect to the GR prediction (Jain & Zhang 2008; Baker, Ferreira, & Skordis 2014).”