论文标题
样品或不采样:检索具有变异推理和归一化流的外球星光谱
To Sample or Not To Sample: Retrieving Exoplanetary Spectra with Variational Inference and Normalising Flows
论文作者
论文摘要
当前的系外行星表征依靠大气检索来量化远程系外行星的关键物理特性。但是,该技术的可伸缩性和效率随着光谱分辨率和正向模型复杂性的增加而应变。随着詹姆斯·韦伯太空望远镜和其他即将到来的任务最近推出,情况变得更加敏锐。机器学习的最新进展提供了基于优化的变异推断,作为执行近似贝叶斯后推断的替代方法。在这项调查中,我们将基于流动的神经网络与新开发的可区分前向模型DIFF-TAU相结合,以在大气检索的背景下进行贝叶斯推断。使用来自真实和模拟光谱数据的示例,我们证明了我们提出的框架的优越性:1)训练我们的神经网络只需要一个观察结果; 2)它会产生与基于抽样的检索相似的高保真后验分布和; 3)需要收敛的远期模型计算少75%。 4.)我们首次在训练有素的神经网络上进行了贝叶斯模型选择。我们提出的框架有助于神经驱动大气检索的最新发展。它的灵活性和速度具有补充基于抽样的方法的潜力,将来可以在大型和复杂的数据集中采用基于采样的方法。
Current endeavours in exoplanet characterisation rely on atmospheric retrieval to quantify crucial physical properties of remote exoplanets from observations. However, the scalability and efficiency of the technique are under strain with increasing spectroscopic resolution and forward model complexity. The situation becomes more acute with the recent launch of the James Webb Space Telescope and other upcoming missions. Recent advances in Machine Learning provide optimisation-based Variational Inference as an alternative approach to perform approximate Bayesian Posterior Inference. In this investigation we combined Normalising Flow-based neural network with our newly developed differentiable forward model, Diff-Tau, to perform Bayesian Inference in the context of atmospheric retrieval. Using examples from real and simulated spectroscopic data, we demonstrated the superiority of our proposed framework: 1) Training Our neural network only requires a single observation; 2) It produces high-fidelity posterior distributions similar to sampling-based retrieval and; 3) It requires 75% less forward model computation to converge. 4.) We performed, for the first time, Bayesian model selection on our trained neural network. Our proposed framework contribute towards the latest development of a neural-powered atmospheric retrieval. Its flexibility and speed hold the potential to complement sampling-based approaches in large and complex data sets in the future.