Second-order weak lensing from modified gravity

Abstract

We explore the sensitivity of weak gravitational lensing to second-order corrections to the spacetime metric within a cosmological adaptation of the parameterized post-Newtonian framework. Whereas one might expect nonlinearities of the gravitational field to introduce non-Gaussianity into the statistics of the lensing convergence field, we show that such corrections are actually always small within a broad class of scalar-tensor theories of gravity. We show this by first computing the weak lensing convergence within our parameterized framework to second order in the gravitational potential, and then computing the relevant post-Newtonian parameters for scalar-tensor gravity theories. In doing so we show that this potential systematic factor is generically negligible, thus clearing the way for weak lensing to provide a direct tracer of mass on cosmological scales for a wide class of gravity theories despite uncertainties in the precise nature of the departures from general relativity.

13 pages, 1 figure; v2: minor edits to match the PRD accepted version

References in corpus (10)

• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Solar System constraints to general f(R) gravity
• Symmetron Cosmology
• COSMOS: 3D weak lensing and the growth of structure
• Cosmic Acceleration and the Helicity-0 Graviton
• Linearized f(R) Gravity: Gravitational Radiation & Solar System Tests
• Galilean-invariant scalar fields can strengthen gravitational lensing
• The Parameterised Post-Newtonian Limit of Fourth-Order Theories of Gravity
• Second post-Newtonian approximation of scalar-tensor theory of gravity
• Dark energy constraints and correlations with systematics from CFHTLS weak lensing, SNLS supernovae Ia and WMAP5

Cited by in corpus (7)

• Galactic rotation curves in hybrid metric-Palatini gravity
• 2PN Light Propagation in the Scalar-Tensor Theory: an $N$-Point-Masses Case
• Investigating scalar-tensor-gravity with statistics of the cosmic large-scale structure
• Expressions for optical scalars and deflection angle at second order in terms of curvature scalars
• Weak Lensing Science, Surveys, and Systematics
• Cosmic Shear E/B-mode Estimation with Binned Correlation Function Data
• Weak lensing corrections to tSZ-lensing cross correlation