We present an updated version of the hmcode augmented halo model that can be used to make accurate predictions of the non-linear matter power spectrum over a wide range of cosmologies. Major improvements include modelling of baryon-acoustic oscillation (BAO) damping in the power spectrum and an updated treatment of massive neutrinos. We fit our model to simulated power spectra and show that we can match the results with an root mean square (RMS) error of 2.5 per cent across a range of cosmologies, scales $k \lt 10\, h\, \mathrm{Mpc}^{-1}$, and redshifts z < 2. The error rarely exceeds 5 per cent and never exceeds 16 per cent. The worst-case errors occur at z ≃ 2, or for cosmologies with unusual dark energy equations of state. This represents a significant improvement over previous versions of hmcode, and over other popular fitting functions, particularly for massive-neutrino cosmologies with high neutrino mass. We also present a simple halo model that can be used to model the impact of baryonic feedback on the power spectrum. This six-parameter physical model includes gas expulsion by active galactic nuclei (AGN) feedback and encapsulates star formation. By comparing this model to data from hydrodynamical simulations, we demonstrate that the power spectrum response to feedback is matched at the <1 per cent level for z < 1 and $k\lt 20\, h\, \mathrm{Mpc}^{-1}$. We also present a single-parameter variant of this model, parametrized in terms of feedback strength, which is only slightly less accurate. We make code available for our non-linear and baryon models at https://github.com/alexander-mead/HMcode and it is also available within camb and soon within class.

中文翻译：

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hmcode-2020：改进了具有重子反馈的非线性宇宙功率谱建模

我们提出了 hmcode 增强光环模型的更新版本，该模型可用于准确预测各种宇宙学中的非线性物质功率谱。主要改进包括功率谱中重子声振荡 (BAO) 阻尼的建模以及对大量中微子的更新处理。我们将我们的模型拟合到模拟功率谱，并表明我们可以将结果与 2.5% 的均方根 (RMS) 误差在一系列宇宙学中匹配，尺度 $k \lt 10\, h\, \mathrm{Mpc }^{-1}$ 和红移 z < 2. 误差很少超过 5%，从不超过 16%。最坏情况的错误发生在 z ≃ 2 处，或者出现在具有不寻常暗能量状态方程的宇宙学中。这代表了对以前版本的 hmcode 以及其他流行的拟合函数的显着改进，特别是对于具有高中微子质量的大质量中微子宇宙学。我们还提出了一个简单的光环模型，可用于模拟重子反馈对功率谱的影响。这个六参数物理模型包括活动星系核 (AGN) 反馈的气体排出和封装恒星形成。通过将该模型与流体动力学模拟的数据进行比较，我们证明了对反馈的功率谱响应在 z < 1% 的水平上匹配。1 和 $k\lt 20\, h\, \mathrm{Mpc}^{-1}$。我们还提出了该模型的单参数变体，根据反馈强度进行了参数化，但准确度略低。我们在 https://github.com/alexander-mead/HMcode 上为我们的非线性和重子模型提供了代码，它也可以在 camb 中使用，很快就会在课堂上使用。