用深度学习融合弱引力透镜与星系聚集数据,提升暗能量研究精度。
Dark Energy Survey Year 3 results: Simulation-based $w$CDM inference from weak lensing and galaxy clustering maps with deep learning: Analysis design
- 基于百万级模拟构建真实宇宙地图,训练图神经网络提取关键特征。
- 在十维参数空间中实现高精度参数约束,使约束力提升2-3倍。
- 适合参与大型巡天数据分析的研究者,尤其关注非高斯信息挖掘。
基于深度学习的数据驱动方法正成为提取宇宙大尺度结构中非高斯信息的强大工具。本文首次构建了结合弱引力透镜与星系聚集图的模拟基推断(SBI)流程,适用于真实的暗能量调查第三年(DES Y3)配置,为后续数据分析做准备。我们基于CosmoGridV1 N体模拟套件开发可扩展的前向模型,在地图层面生成超百万个自洽的DES Y3模拟样本。利用该大数据集,我们在球面几何下训练深度图卷积神经网络,学习低维特征以近似最大化与目标参数的互信息。这些压缩特征支持通过归一化流在十维参数空间中进行神经密度估计,涵盖wCDM、内在对齐及星系线性偏置参数,并对恒星物理、光度红移和剪切偏差等噪声项进行边际化处理。为确保鲁棒性,我们通过前向模型中的系统污染及独立的Buzzard星系目录生成的合成观测进行了广泛验证。预测结果表明,相比基准两点统计量方法,Ω_m - S_8平面的约束能力提升2-3倍,有效打破参数退化,展示了深度学习驱动的SBI分析在下一代第四阶段宽视场成像巡天中的巨大潜力。
原文摘要 · Abstract (English)
Data-driven approaches using deep learning are emerging as powerful techniques to extract non-Gaussian information from cosmological large-scale structure. This work presents the first simulation-based inference (SBI) pipeline that combines weak lensing and galaxy clustering maps in a realistic Dark Energy Survey Year 3 (DES Y3) configuration and serves as preparation for a forthcoming analysis of the survey data. We develop a scalable forward model based on the CosmoGridV1 suite of N-body simulations to generate over one million self-consistent mock realizations of DES Y3 at the map level. Leveraging this large dataset, we train deep graph convolutional neural networks on the full survey footprint in spherical geometry to learn low-dimensional features that approximately maximize mutual information with target parameters. These learned compressions enable neural density estimation of the implicit likelihood via normalizing flows in a ten-dimensional parameter space spanning cosmological $w$CDM, intrinsic alignment, and linear galaxy bias parameters, while marginalizing over baryonic, photometric redshift, and shear bias nuisances. To ensure robustness, we extensively validate our inference pipeline using synthetic observations derived from both systematic contaminations in our forward model and independent Buzzard galaxy catalogs. Our forecasts yield significant improvements in cosmological parameter constraints, achieving $2-3\times$ higher figures of merit in the $Ω_m - S_8$ plane relative to our implementation of baseline two-point statistics and effectively breaking parameter degeneracies through probe combination. These results demonstrate the potential of SBI analyses powered by deep learning for upcoming Stage-IV wide-field imaging surveys.
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