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arXiv 2303.08899astro-ph.COgr-qc
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e-MANTIS仿真器:f(R)CDM宇宙学中非线性物质功率谱的快速预测

The e-MANTIS emulator: fast predictions of the non-linear matter power spectrum in $f(R)$CDM cosmology

Iñigo Sáez-Casares, Yann Rasera, Baojiu Li

AI总结:

本文发布e-MANTIS仿真器,利用高斯过程回归对f(R)CDM与ΛCDM模拟的功率谱增强因子进行快速插值,在宽广参数空间内实现优于3%的预测精度,可用于弱引力透镜约束修正引力。

摘要:

为了在宇宙学尺度上探测引力修正,需要精确的理论预测。N体模拟对于探索结构形成的非线性区域是必需的,但非常耗时。在这项工作中,我们发布了一个新的公开仿真器,名为e-MANTIS,它在使用ECOSMOG运行的f(R)修正引力宇宙学模拟的预测之间执行精确且快速的插值。我们对一个宽广的三维参数空间进行采样,该参数空间由当前背景标量场值$10^{-7}<\left|f_{R_0}\right|<10^{-4}$、物质密度$0.24<Ω_\mathrm{m}<0.39$以及原初功率谱归一化$0.6<σ_8<1.0$给出,使用拉丁超立方采样了110个点。对于每个模型,我们执行成对的f(R)CDM和ΛCDM模拟,覆盖有效体积为$\left(560 \\, h^{-1}\mathrm{Mpc}\right)^3$,质量分辨率约为$\sim 2 \times 10^{10} h^{-1} M_\odot$。我们使用高斯过程回归方法为物质功率谱增强因子$B(k)=P_{f(R)}(k)/P_{Λ\mathrm{CDM}}(k)$构建仿真器。该增强因子在很大程度上独立于$h$、$n_{s}$和$Ω_{b}$,这降低了相关宇宙学参数空间的维度。此外,它比原始功率谱对统计误差和系统误差更具鲁棒性,从而大大减少了我们的计算需求。根据我们对数值系统误差的专门研究,所得仿真器在整个宇宙学参数空间内,对于尺度$0.03 \\ h\mathrm{Mpc}^{-1} < k < 7 \\ h\mathrm{Mpc}^{-1}$和红移$0 < z < 2$,估计最大误差为$3\\%$,而在大多数情况下精度优于$1\\%$。这样的仿真器可用于通过弱引力透镜分析来约束f(R)引力。

英文摘要:

In order to probe modifications of gravity at cosmological scales, one needs accurate theoretical predictions. N-body simulations are required to explore the non-linear regime of structure formation but are very time consuming. In this work, we release a new public emulator, dubbed e-MANTIS, that performs an accurate and fast interpolation between the predictions of $f(R)$ modified gravity cosmological simulations, run with ECOSMOG. We sample a wide 3D parameter space given by the current background scalar field value $10^{-7}<\left|f_{R_0}\right|<10^{-4}$, matter density $0.24<Ω_\mathrm{m}<0.39$, and primordial power spectrum normalisation $0.6<σ_8<1.0$, with 110 points sampled from a Latin Hypercube. For each model we perform pairs of $f(R)$CDM and $Λ$CDM simulations covering an effective volume of $\left(560 \, h^{-1}\mathrm{Mpc}\right)^3$ with a mass resolution of $\sim 2 \times 10^{10} h^{-1} M_\odot$. We build an emulator for the matter power spectrum boost $B(k)=P_{f(R)}(k)/P_{Λ\mathrm{CDM}}(k)$ using a Gaussian Process Regression method. The boost is mostly independent of $h$, $n_{s}$, and $Ω_{b}$, which reduces the dimensionality of the relevant cosmological parameter space. Additionally, it is more robust against statistical and systematic errors than the raw power spectrum, thus strongly reducing our computational needs. According to our dedicated study of numerical systematics, the resulting emulator has an estimated maximum error of $3\%$ across the whole cosmological parameter space, for scales $0.03 \ h\mathrm{Mpc}^{-1} < k < 7 \ h\mathrm{Mpc}^{-1}$, and redshifts $0 < z < 2$, while in most cases the accuracy is better than $1\%$. Such an emulator could be used to constrain $f(R)$ gravity with weak lensing analyses

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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