FLAMINGO项目：对用于推断宇宙学参数的星系团计数模型预测中的系统误差的评估
The FLAMINGO Project: An assessment of the systematic errors in the predictions of models for galaxy cluster counts used to infer cosmological parameters
AI总结：
本研究依托FLAMINGO流体动力学模拟，评估传统星系团计数模型各组分导致的计数与宇宙学参数偏差，发现现有DMO HMF模型差异显著，未来巡天需改进标度关系、重子效应等多类模型组分。
摘要：
星系团计数历来对宇宙学参数测量至关重要，即将开展的巡天将大幅降低统计误差。要发挥当前及未来星系团巡天的潜力，预测丰度的理论不确定性必须小于统计误差。用于预测星系团计数的模型通常将纯暗物质（DMO）暗晕质量函数（HMF）模型与观测量-质量关系相结合，该关系被假定为具有对数正态弥散的幂律形式。我们利用FLAMINGO系列宇宙学流体动力学模拟，量化传统模型不同组成部分导致的星系团计数及宇宙学参数偏差。对于观测量质量代理，我们聚焦于表征热苏尼亚耶夫-泽尔多维奇效应的Compton-Y参数，该参数预计能产生相对接近质量选择样本的星系团样本。我们基于现有（Planck和SPT）及即将开展的（Simons Observatory）巡天构建了三个模拟样本。我们忽略测量不确定性，将计数偏差和推断得到的宇宙学参数偏差与各巡天的泊松误差进行比较。我们发现，广泛使用的DMO HMF模型之间存在显著差异，且与FLAMINGO的DMO版本也存在显著差异，这给所有三个巡天带来了显著偏差。对于即将开展的巡天，所有额外的模型组成部分都亟需大幅改进，即观测量-质量标度关系及其相关弥散的拟合函数形式、标度关系的先验，以及与反馈过程相关的重子效应对HMF影响的先验。
英文摘要：
Galaxy cluster counts have historically been important for the measurement of cosmological parameters and upcoming surveys will greatly reduce the statistical errors. To exploit the potential of current and future cluster surveys, theoretical uncertainties on the predicted abundance must be smaller than the statistical errors. Models used to predict cluster counts typically combine a model for the dark matter only (DMO) halo mass function (HMF) with an observable - mass relation that is assumed to be a power-law with lognormal scatter. We use the FLAMINGO suite of cosmological hydrodynamical simulations to quantify the biases in the cluster counts and cosmological parameters resulting from the different ingredients of conventional models. For the observable mass proxy we focus on the Compton-Y parameter quantifying the thermal Sunyaev-Zel'dovich effect, which is expected to result in cluster samples that are relatively close to mass-selected samples. We construct three mock samples based on existing (Planck and SPT) and upcoming (Simons Observatory) surveys. We ignore measurement uncertainties and compare the biases in the counts and inferred cosmological parameters to each survey's Poisson errors. We find that widely used models for the DMO HMF differ significantly from each other and from the DMO version of FLAMINGO, leading to significant biases for all three surveys. For upcoming surveys, dramatic improvements are needed for all additional model ingredients, i.e. the functional forms of the fits to the observable-mass scaling relation and the associated scatter, the priors on the scaling relation and the prior on baryonic effects associated with feedback processes on the HMF.
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