Field-based physical inference from peculiar velocity tracers
Field-based physical inference from peculiar velocity tracers
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DOI：
10.1093/mnras/stac3346
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发表时间：
2022-03
影响因子：
4.8
通讯作者：
James Prideaux-Ghee;F. Leclercq;G. Lavaux;A. Heavens;J. Jasche
中科院分区：
文献类型：
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作者：
James Prideaux-Ghee;F. Leclercq;G. Lavaux;A. Heavens;J. Jasche
我们提出了一种概念验证贝叶斯分层建模方法来重建受特殊速度观测约束的初始宇宙物质密度场。它使用暗物质引力演化模型将初始条件与后期观测联系起来，将后期密度和速度场重建为自然副产品。我们通过采用星系贝叶斯原点重建（$\small {BORG}$）算法来实现这种基于场的物理推理方法，该算法通过使用哈密顿蒙特卡罗采样探索高维后验。我们使用随机的示踪剂组测试该方法的自洽性，并在更复杂的场景中评估其准确性，其中特殊的速度示踪剂是从 $\small {GADGET2}$ N 体模拟中提取的模拟光环。我们发现我们的框架自洽地推断了初始条件、密度和速度场，并对模型错误指定表现出一定的鲁棒性。与约束高斯随机场/维纳滤波的方法相比，分层模型产生更准确的最终密度和速度场重建。它还使我们能够通过特殊的速度观测来约束初始条件，在这方面补充了基于替代宇宙学观测（例如星系团或弱透镜）的其他基于场的方法。
We present a proof-of-concept Bayesian hierarchical modelling approach to reconstruct the initial cosmic matter density field constrained by peculiar velocity observations. Using a model for the gravitational evolution of dark matter to connect the initial conditions to late-time observations, it reconstructs the late-time density and velocity fields as natural byproducts. We implement this field-based physical inference approach by adapting the Bayesian Origin Reconstruction from Galaxies ($\small {BORG}$) algorithm, which explores the high-dimensional posterior through the use of Hamiltonian Monte Carlo sampling. We test the self-consistency of the method using random sets of tracers, and assess its accuracy in a more complex scenario where peculiar velocity tracers are mock haloes drawn from $\small {GADGET2}$ N-body simulations. We find that our framework self-consistently infers the initial conditions, density and velocity fields, and shows some robustness to model mis-specification. Compared with the approach of constrained Gaussian random fields/Wiener filtering, the hierarchical model produces more accurate final density and velocity field reconstructions. It also allows us to constrain the initial conditions by peculiar velocity observations, complementing in this aspect other field-based approaches based on alternative cosmological observables such as galaxy clustering or weak lensing.