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arXiv 2409.12937astro-ph.CO
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用于LSS基于EFT的全形状分析的HOD信息先验

HOD-informed prior for EFT-based full-shape analyses of LSS

Hanyu Zhang, Marco Bonici, Guido D'Amico, Simone Paradiso, Will J. Percival

AI总结:

提出用HOD模拟构建EFT冗余参数的信息先验,增强全形状LSS分析稳健性,并显著改善ΛCDM及扩展模型的宇宙学参数恢复。

摘要:

为提升大尺度结构全形状分析的性能,我们考虑对有效场论(EFT)冗余参数采用由晕占据分布(HOD)提供信息的先验。我们利用10 000组HOD参数,在32个具有不同宇宙学参数的模拟盒中生成了320 000个模拟星系目录。我们使用EFT模型的快速模拟器测量并拟合红移空间功率谱,并将所得的最佳拟合EFT参数分布用于构建该先验。该先验有效约束了EFT冗余参数空间,将其限制在能够被EFT模型良好拟合的HOD模拟样本空间内。我们测试了该先验在不同配置下的稳定性,包括改变HOD样本分布以及纳入十六极矩的影响。我们发现,HOD信息先验以及由其导出的宇宙学参数约束均具有稳健性。采用标准EFT先验的宇宙学拟合会受到先验效应影响,有时无法在贝叶斯可信区间内恢复真实宇宙学;而HOD信息先验缓解了这些问题,并显著改善了ΛCDM及其扩展模型的宇宙学参数恢复效果。本工作为当前和未来星系巡天中更优的大尺度结构全形状分析奠定了基础,使其成为解答宇宙学关键问题的宝贵工具。

英文摘要:

To improve the performance of full-shape analyses of large-scale structure, we consider using a halo occupation distribution (HOD)-informed prior for the effective field theory (EFT) nuisance parameters. We generate 320 000 mock galaxy catalogs using 10 000 sets of HOD parameters across 32 simulation boxes with different cosmologies. We measure and fit the redshift-space power spectra using a fast emulator of the EFT model, and the resulting best-fit EFT parameter distributions are used to create the prior. This prior effectively constrains the EFT nuisance parameter space, limiting it to the space of HOD-mocks that can be well fit by a EFT model. We have tested the stability of the prior under different configurations, including the effect of varying the HOD sample distribution and the inclusion of the hexadecapole moment. We find that our HOD-informed prior and the cosmological parameter constraints derived using it are robust. While cosmological fits using the standard EFT prior suffer from prior effects, sometimes failing to recover the true cosmology within Bayesian credible intervals, the HOD-informed prior mitigates these issues and significantly improves cosmological parameter recovery for $Λ$CDM and beyond. This work lays the foundation for better full-shape large-scale structure analyses in current and upcoming galaxy surveys, making it a valuable tool for addressing key questions in cosmology.

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