论文标题
lyman-$α$ forest的模拟器超过$λ$ CDM宇宙学
An emulator for the Lyman-$α$ forest in beyond-$Λ$CDM cosmologies
论文作者
论文摘要
解释对Lyman-$α$森林通量功率谱的观察需要在少数昂贵的模拟之间进行插值。我们提出了一个高斯工艺模拟器，该过程对1D通量功率谱进行建模，这是小规模线性物质功率谱的振幅和斜率的函数，以及感兴趣的时期层间介质的状态（$ 2 <z <4 $）。此参数化可以预测扩展宇宙学模型中未明确包含的扩展宇宙学模型中的通量功率谱，从而消除了对$λ$ cdm的许多扩展的构造构造模拟器的需求。我们的仿真器适用于宇宙学，其中线性物质功率谱仅通过在感兴趣的时代的幅度和斜率以及Eboss/desi数据探索的策略中描述为级别的准确性百分比。我们为大规模的中微子宇宙学展示了这一点，其中模拟器能够预测$σm_ν= 0.3 $ eV中微子宇宙学以降低训练模拟中的大量中微子，以预测$σm_ν= 0.3 $ eV中微子宇宙学的通量功率谱。需要进一步的参数来描述线性功率中具有鲜明特征的模型，例如温暖或轻轴暗物质。这项工作将促进即将到来的DESI数据与观察宇宙微波背景的结合，以获得对中微子质量和其他扩展的约束至$λ$ CDM宇宙学。
Interpreting observations of the Lyman-$α$ forest flux power spectrum requires interpolation between a small number of expensive simulations. We present a Gaussian process emulator modelling the 1D flux power spectrum as a function of the amplitude and slope of the small-scale linear matter power spectrum, and the state of the intergalactic medium at the epoch of interest ($2 < z < 4$). This parameterisation enables the prediction of the flux power spectrum in extended cosmological models that are not explicitly included in the training set, eliminating the need to construct bespoke emulators for a number of extensions to $Λ$CDM. Our emulator is appropriate for cosmologies in which the linear matter power spectrum is described to percent level accuracy by just an amplitude and slope across the epoch of interest, and in the regime probed by eBOSS/DESI data. We demonstrate this for massive neutrino cosmologies, where the emulator is able to predict the flux power spectrum in a $Σm_ν=0.3$ eV neutrino cosmology to sub-percent accuracy, without including massive neutrinos in the training simulations. Further parameters would be required to describe models with sharp features in the linear power, such as warm or light axion dark matter. This work will facilitate the combination of upcoming DESI data with observations of the cosmic microwave background, to obtain constraints on neutrino mass and other extensions to $Λ$CDM cosmology.
