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 ΛCDM. 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 Σ m_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 ΛCDMcosmology.

解释 Lyman-α 森林通量功率谱的观察结果需要在少量昂贵的模拟之间进行插值。我们提出了一个高斯过程仿真器，将一维通量功率谱建模为小尺度线性物质功率谱的幅度和斜率的函数，以及感兴趣时期 (2 < z < 4) 的星系间介质状态。这种参数化能够预测未明确包含在训练集中的扩展宇宙学模型中的通量功率谱，从而无需为 ΛCDM 的许多扩展构建定制仿真器。我们的模拟器适用于宇宙学，在这种宇宙学中，线性物质功率谱被描述为仅通过感兴趣时期的幅度和斜率来达到百分比水平精度，并在 eBOSS/DESI 数据探测的范围内。我们在大规模中微子宇宙学中证明了这一点，其中模拟器能够预测 Σ m 中的通量功率谱_ν = 0.3 eV 中微子宇宙学达到亚百分比精度，在训练模拟中不包括大量中微子。需要进一步的参数来描述具有线性功率特征的模型，例如暖或光轴子暗物质。这项工作将有助于将即将到来的 DESI 数据与宇宙微波背景观测相结合，以获得对中微子质量和 ΛCDM 宇宙学其他扩展的约束。