All-sky modelling requirements for Bayesian 21 cm power spectrum estimation with bayeseor
All-sky modelling requirements for Bayesian 21 cm power spectrum estimation with bayeseor
复制标题
使用 bayeseor 进行贝叶斯 21 cm 功率谱估计的全天空建模要求
DOI：
10.1093/mnras/stad401
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发表时间：
2023
影响因子：
4.8
通讯作者：
Pober, Jonathan C.
中科院分区：
文献类型：
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作者：
Burba, Jacob;Sims, Peter H.;Pober, Jonathan C.
我们提出了一项基于模拟的综合研究，用于在分析边缘化前景参数时进行 21 cm 功率谱恢复的贝叶斯或代码。为了解释 21 cm 信号和污染性前景发射之间的协方差，贝叶斯或在贝叶斯框架内联合构建这两个信号的模型。由于计算限制，前向模型是使用图像域中的受限视场（FoV）构建的。当再电离污染物的唯一纪元是噪声和前景时，我们证明，当该正向建模区域之外的天空发射分量在前景和 21 cm 信号之间的动态范围水平上被光束降低权重时，贝叶斯或可以准确地恢复 21 cm 功率谱。然而，当全天空前景发射与旁瓣高于此阈值并延伸到地平线的真实仪器主波束一起包含时，恢复的功率谱会受到受限 FoV 模型之外的未建模天空发射的污染。将组合的宇宙学和前景模型扩展到覆盖整个天空在计算上是令人望而却步的。为了解决这个问题，我们提出了贝叶斯或贝叶斯的修改版本，它允许全天空前景模型，而建模的 21 厘米信号仅保留在望远镜的主视场内。通过此修改，在相当大的计算集群上运行全天空贝叶斯分析将是可行的。我们还讨论了进一步减少全天空前景建模需求的几个未来方向，包括宽视场前景减法、利用锥形函数的图像域似然以及仪器主光束设计。
We present a comprehensive simulation-based study of thebayeseorcode for 21 cm power spectrum recovery when analytically marginalizing over foreground parameters. To account for covariance between the 21 cm signal and contaminating foreground emission,bayeseorjointly constructs models for both signals within a Bayesian framework. Due to computational constraints, the forward model is constructed using a restricted field of view (FoV) in the image domain. When the only Epoch of Reionization contaminants are noise and foregrounds, we demonstrate thatbayeseorcan accurately recover the 21 cm power spectrum when the component of sky emission outside this forward-modelled region is downweighted by the beam at the level of the dynamic range between the foreground and 21 cm signals. However, when all-sky foreground emission is included along with a realistic instrument primary beam with sidelobes above this threshold extending to the horizon, the recovered power spectrum is contaminated by unmodelled sky emission outside the restricted FoV model. Expanding the combined cosmological and foreground model to cover the whole sky is computationally prohibitive. To address this, we present a modified version ofbayeseorthat allows for an all-sky foreground model, while the modelled 21 cm signal remains only within the primary FoV of the telescope. With this modification, it will be feasible to run an all-skybayeseoranalysis on a sizeable compute cluster. We also discuss several future directions for further reducing the need to model all-sky foregrounds, including wide-field foreground subtraction, an image-domain likelihood utilizing a tapering function, and instrument primary beam design.