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arXiv · 0804.4343

The effect of modified gravity on weak lensing

Shinji Tsujikawa·Takayuki Tatekawa
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Abstract

We study the effect of modified gravity on weak lensing in a class of scalar-tensor theory that includes $f(R)$ gravity as a special case. These models are designed to satisfy local gravity constraints by having a large scalar-field mass in a region of high curvature. Matter density perturbations in these models are enhanced at small redshifts because of the presence of a coupling $Q$ that characterizes the strength between dark energy and non-relativistic matter. We compute a convergence power spectrum of weak lensing numerically and show that the spectral index and the amplitude of the spectrum in the linear regime can be significantly modified compared to the $Λ$CDM model for large values of $|Q|$ of the order of unity. Thus weak lensing provides a powerful tool to constrain such large coupling scalar-tensor models including $f(R)$ gravity.

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Shinji Tsujikawa, Takayuki Tatekawa. 2008-08-18. The effect of modified gravity on weak lensing. https://doi.org/10.1016/j.physletb.2008.06.052

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