We present and test a framework that models the three-dimensional distribution of mass in the Universe as a function of cosmological and astrophysical parameters. Our approach combines two different techniques: a rescaling algorithm that modifies the cosmology of gravity-only N-body simulations, and a baryonification algorithm which mimics the effects of astrophysical processes induced by baryons, such as star formation and AGN feedback. We show how this approach can accurately reproduce the effects of baryons on the matter power spectrum of various state-of-the-art hydro-dynamical simulations (EAGLE, Illustris, Illustris-TNG, Horizon-AGN, and OWLS,Cosmo-OWLS and BAHAMAS), to percent level from very large down to small, highly nonlinear scales, k= 5 h/Mpc, and from z=0 up to z=2. We highlight that, thanks to the heavy optimisation of the algorithms, we can obtain these predictions for arbitrary baryonic models and cosmology (including massive neutrinos and dynamical dark energy models) with an almost negligible CPU cost. Therefore, this approach is efficient enough for cosmological data analyses. With these tools in hand we explore the degeneracies between cosmological and astrophysical parameters in the nonlinear mass power spectrum. Our findings suggest that after marginalising over baryonic physics, cosmological constraints inferred from weak gravitational lensing should be moderately degraded.

中文翻译：

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将宇宙的大规模质量密度场建模为宇宙学和重子物理学的函数

我们提出并测试了一个框架，该框架将宇宙中质量的三维分布建模为宇宙学和天体物理参数的函数。我们的方法结合了两种不同的技术：一种修改纯重力 N 体模拟宇宙学的重新缩放算法，以及一种模拟由重子引起的天体物理过程影响的重子化算法，例如恒星形成和 AGN 反馈。我们展示了这种方法如何准确地再现重子对各种最先进的流体动力学模拟（EAGLE、Illustris、Illustris-TNG、Horizo​​n-AGN 和 OWLS、Cosmo-OWLS 和BAHAMAS)，从非常大到小的高度非线性尺度，k=5h/Mpc，从 z=0 到 z=2。我们强调，由于算法的大量优化，我们可以以几乎可​​以忽略不计的 CPU 成本获得对任意重子模型和宇宙学（包括大量中微子和动态暗能量模型）的这些预测。因此，这种方法对于宇宙学数据分析来说足够有效。有了这些工具，我们将探索非线性质量功率谱中宇宙学和天体物理参数之间的简并性。我们的研究结果表明，在对重子物理学进行边缘化之后，从弱引力透镜推断出的宇宙学约束应该适度降低。这种方法对于宇宙学数据分析来说足够有效。有了这些工具，我们将探索非线性质量功率谱中宇宙学和天体物理参数之间的简并性。我们的研究结果表明，在对重子物理学进行边缘化之后，从弱引力透镜推断出的宇宙学约束应该适度降低。这种方法对于宇宙学数据分析来说足够有效。有了这些工具，我们将探索非线性质量功率谱中宇宙学和天体物理参数之间的简并性。我们的研究结果表明，在对重子物理学进行边缘化之后，从弱引力透镜推断出的宇宙学约束应该适度降低。