Weak lensing probes of modified gravity

Journal Article · Fri Aug 15 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.78.043002· OSTI ID:21250445

Schmidt, Fabian ^[1]

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1. Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637-1433 (United States) and Kavli Institute for Cosmological Physics, Chicago, Illinois 60637-1433 (United States)

We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.

• OSTI ID: 21250445
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 4 Vol. 78; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
99 GENERAL AND MISCELLANEOUS
COMPARATIVE EVALUATIONS
CORRELATIONS
COSMOLOGY
DISTURBANCES
EVOLUTION
EXPANSION
FORECASTING
GALAXIES
GENERAL RELATIVITY THEORY
GRAVITATION
GRAVITATIONAL LENSES
GROWTH FACTORS
MODIFICATIONS
NONLUMINOUS MATTER
PERTURBATION THEORY
POTENTIALS
PROBES
RED SHIFT
RELICT RADIATION
SPECTRA