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arXiv · 2406.09204

Extending MGCAMB tests of gravity to nonlinear scales

Zhuangfei Wang·Daniela Saadeh·Kazuya Koyama·Levon Pogosian·Benjamin Bose·Lanyang Yi·Gong-Bo Zhao
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Abstract

Modified Growth with {\tt CAMB} ({\tt MGCAMB}) is a patch for the Einstein-Boltzmann solver {\tt CAMB} for cosmological tests of gravity. Until now, {\tt MGCAMB} was limited to scales well-described by linear perturbation theory. In this work, we extend the framework with a phenomenological model that can capture nonlinear corrections in a broad range of modified gravity theories. The extension employs the publicly available halo model reaction code {\tt ReACT}, developed for modeling the nonlinear corrections to cosmological observables in extensions of the $\Lambda$CDM model. The nonlinear extension makes it possible to use a wider range of data from large scale structure surveys, without applying a linear scale cut. We demonstrate that, with the 3$\times$2pt Dark Energy Survey data, we achieve a stronger constraint on the linear phenomenological functions $\mu$ and $\Sigma$, after marginalzing over the additional nonlinear parameter $p_1$, compared to the case without the nonlinear extension and using a linear cut. The new version of {\tt MGCAMB} is now forked with {\tt CAMB} on GitHub allowing for compatibility with future upgrades.

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Zhuangfei Wang, Daniela Saadeh, Kazuya Koyama, Levon Pogosian, Benjamin Bose, Lanyang Yi, Gong-Bo Zhao. 2024-06-13. Extending MGCAMB tests of gravity to nonlinear scales. https://arxiv.org/abs/2406.09204

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