Modified Growth with CAMB (MGCAMB) is a patch for the Einstein-Boltzmann solver CAMB for cosmological tests of gravity. Until now, 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 ReACT, developed for modeling the nonlinear corrections to cosmological observables in extensions of the ΛCDM 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 3×2pt Dark Energy Survey data, we achieve a stronger constraint on the linear phenomenological functions μ and Σ, 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 MGCAMB is now forked with CAMB on GitHub allowing for compatibility with future upgrades.

中文翻译：

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将 MGCAMB 重力测试扩展到非线性标度


Modified Growth with CAMB （MGCAMB） 是 Einstein-Boltzmann 求解器 CAMB 的补丁，用于引力的宇宙学测试。到目前为止，MGCAMB 仅限于线性微扰理论所充分描述的尺度。在这项工作中，我们用一个现象学模型扩展了框架，该模型可以在广泛的修正引力理论中捕捉非线性修正。该扩展采用了公开可用的光晕模型反应代码 ReACT，该代码是为在 ΛCDM 模型的扩展中对宇宙学可观测物的非线性校正进行建模而开发的。非线性延伸使得可以使用来自大规模结构测量的更广泛数据，而无需应用线性比例切割。我们证明，使用 3×2pt 暗能量巡天数据，与没有非线性延伸和使用线性切割的情况相比，在边缘化额外的非线性参数 p₁ 之后，我们对线性现象函数 μ 和 Σ 实现了更强的约束。新版本的 MGCAMB 现在在 GitHub 上与 CAMB 分叉，允许与未来的升级兼容。