The Atacama Cosmology Telescope: map-based noise simulations for DR6
The Atacama Cosmology Telescope: map-based noise simulations for DR6
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DOI：
10.1088/1475-7516/2023/11/073
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发表时间：
2023-03
影响因子：
6.4
通讯作者：
Zachary R. Atkins;A. Duivenvoorden;W. Coulton;F. J. Qu;S. Aiola;E. Calabrese;G. Chesmore;Steve K. Choi;M. Devlin;J. Dunkley;Carlos Herv'ias-Caimapo;Yilun Guan;A. L. Posta;Zack Li;T. Louis;M. Madhavacheril;K. Moodley;S. Naess;F. Nati;M. Niemack;L. Page;R. Puddu;M. Salatino;C. Sif'on;S. Staggs;C. Vargas;E. Vavagiakis;Edward J. Wollack
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文献类型：
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作者：
Zachary R. Atkins;A. Duivenvoorden;W. Coulton;F. J. Qu;S. Aiola;E. Calabrese;G. Chesmore;Steve K. Choi;M. Devlin;J. Dunkley;Carlos Herv'ias-Caimapo;Yilun Guan;A. L. Posta;Zack Li;T. Louis;M. Madhavacheril;K. Moodley;S. Naess;F. Nati;M. Niemack;L. Page;R. Puddu;M. Salatino;C. Sif'on;S. Staggs;C. Vargas;E. Vavagiakis;Edward J. Wollack
宇宙微波背景（CMB）数据集的统计能力越来越强，这就要求我们在理解它们的噪声特性方面付出相应的努力。来自地面仪器的地图噪声主要是由大尺度的相关性引起的，这给建模带来了挑战。本文建立了阿塔卡马宇宙学望远镜数据发布6 （ACT DR6）图中复杂噪声协方差结构的新模型。我们首先列举了大气和ACT扫描策略结合产生的噪声特性。然后，我们规定了一类基于映射的高斯噪声模型，包括一种新的基于小波的方法，该方法使用定向小波核来建模相关的仪器噪声。这些模式是经验的，其唯一的输入是对天空同一区域的少量独立实现。我们通过绘制噪声实现的集合来评估这些模型与ACT DR6数据的性能。将这些模拟应用于ACT DR6功率谱管道，与假设噪声特性由其功率谱唯一描述的解析表达式相比，发现协方差矩阵对角线中有~ 20%的过剩。与我们的公共代码mnms一起，这项工作为ACT DR6和未来的地面CMB实验（如西蒙斯天文台（SO））的科学管道建立了必要的元素。
The increasing statistical power of cosmic microwave background (CMB) datasets requires a commensurate effort in understanding their noise properties. The noise in maps from ground-based instruments is dominated by large-scale correlations, which poses a modeling challenge. This paper develops novel models of the complex noise covariance structure in the Atacama Cosmology Telescope Data Release 6 (ACT DR6) maps. We first enumerate the noise properties that arise from the combination of the atmosphere and the ACT scan strategy. We then prescribe a class of Gaussian, map-based noise models, including a new wavelet-based approach that uses directional wavelet kernels for modeling correlated instrumental noise. The models are empirical, whose only inputs are a small number of independent realizations of the same region of sky. We evaluate the performance of these models against the ACT DR6 data by drawing ensembles of noise realizations. Applying these simulations to the ACT DR6 power spectrum pipeline reveals a ∼ 20% excess in the covariance matrix diagonal when compared to an analytic expression that assumes noise properties are uniquely described by their power spectrum. Along with our public code, mnms, this work establishes a necessary element in the science pipelines of both ACT DR6 and future ground-based CMB experiments such as the Simons Observatory (SO).