发表机构
University of Oxford; Université de Strasbourg（牛津大学; 斯特拉斯堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过联合测量宇宙切变与tSZ效应及CIB的交叉关联，提出对CIB光谱参数化的方法，证明对前景不确定性稳健，结果支持低$S_8$值，为未来巡天提供框架。
AI 中文摘要
弱引力透镜（WL）与热Sunyaev-Zel'dovich（tSZ）效应之间的交叉关联探测了低红移（$z\lesssim1$）下物质分布与重子热状态之间的联系。此类测量中的一个关键系统效应是河外前景的污染，特别是宇宙红外背景（CIB）。这里我们用少量物理动机的光谱参数来描述CIB的光谱能量分布（SED），这些参数根据星系中辐射场强度的外部测量进行校准。其不确定性随后在分量分离中传播到恢复的WL×tSZ信号中，在多重频率交叉功率谱层面而非地图层面。将该方法应用于暗能量巡天的宇宙切变和普朗克的频率图，我们表明所得的WL×tSZ功率谱测量对有效CIB光谱指数、射电源污染以及SED的尺度和红移依赖性的变化不敏感。这些测量对现实的前景不确定性是稳健的，支持其作为重子反馈和宇宙学探针的使用，并为未来高精度巡天提供了框架。我们将测量结果与Flamingo流体动力学模拟套件进行比较，发现它们与Flamingo对低物质涨落振幅（以$S_8$参数化）的预测相容，强烈不利于普朗克偏好的较大$S_8$。该结果独立于Flamingo中建模的重子反馈的影响。
英文摘要
The cross-correlation between weak lensing (WL) and the thermal Sunyaev-Zel'dovich (tSZ) effect probes the connection between the matter distribution and the thermal state of baryons at low redshift ($z\lesssim1$). A key systematic in such measurements is contamination by extragalactic foregrounds, particularly the cosmic infrared background (CIB). Here we describe the CIB spectral energy distribution (SED) with a small number of physically motivated spectral parameters, calibrated against external measurements of the radiation field intensity in galaxies. Their uncertainty is then propagated into the recovered WL$\times$tSZ signal in component separation at the level of the multi-frequency cross-power spectra rather than the map level. Applying this method to cosmic shear from the Dark Energy Survey and frequency maps from Planck, we show that the resulting measurements of the WL$\times$tSZ power spectrum are insensitive to variations in the effective CIB spectral index, radio source contamination, and the scale and redshift dependence of the SED. The measurements are robust to realistic foreground uncertainties, supporting their use as probes of baryonic feedback and cosmology, and providing a framework for future high-precision surveys. We compare our measurements with the Flamingo suite of hydrodynamical simulations and find that they are compatible with the Flamingo predictions for a low amplitude of matter fluctuations, parametrised by $S_8$, strongly disfavouring the larger $S_8$ preferred by Planck. This result is independent of the impact of baryonic feedback as modelled in Flamingo.
Comments23 pages, 12 figures, submitted to Physical Review D
