论文标题
CMB B模式后估计和原始重力波信号的重建的贝叶斯ILC方法
A Bayesian ILC method for CMB B-mode posterior estimation and reconstruction of primordial gravity wave signal
论文作者
论文摘要
宇宙微波背景（CMB）辐射B模式偏振信号包含通货膨胀过程中产生的原始度量扰动的独特特征。在观测地图中，弱CMB B模式信号与强端污染的分离是一项复杂的任务，拟议的新一代低噪声卫星任务与该引力背景的弱信号水平竞争。在本文中，我们首次采用了前景独立于模型的内部线性组合（ILC）方法来重建CMB B模式信号，该信号使用模拟观测值对膨胀和宇宙起源（PICO）的6个频带的大型频带的大型尺度上的模拟观测值（PICO）。我们使用ILC方法估算了B模式角功率谱的交织GIBBS步骤和清除的MAP样品后，估计关节CMB B模式后密度。我们扩展并改善了较早报道的贝叶斯ILC方法，用于通过在ILC重量估计期间在两个阶段引入噪声偏置校正来分析弱CMB B模式重建。通过对贝叶斯ILC方法进行$ 200 $的蒙特卡洛模拟，我们发现我们的方法可以在天空的大角度尺度上重建CMB信号和关节后密度。我们估计了CMB B模式的边际密度的Blackwell-Rao统计数据，并使用它们来估计标量与张量比$ r $的关节密度和镜头功率谱振幅$ a^{\ textrm {lens}}} $。使用$ 200 $的蒙特卡洛模拟删除方法，我们发现我们的方法可以实现对原始重力波信号$ r $ r $的无偏见，其$ r \ geqslant 0.01 $的水平超过8 $σ$。
The Cosmic Microwave Background (CMB) radiation B mode polarization signal contains the unique signature of primordial metric perturbations produced during the inflation. The separation of the weak CMB B-mode signal from strong foreground contamination in observed maps is a complex task, and proposed new generation low noise satellite missions compete with the weak signal level of this gravitational background. In this article, for the first time, we employ a foreground model-independent internal linear combination (ILC) method to reconstruct the CMB B mode signal using simulated observations over large angular scales of the sky of 6 frequency bands of future generation CMB mission Probe of Inflation and Cosmic Origins (PICO). We estimate the joint CMB B mode posterior density following the interleaving Gibbs steps of B mode angular power spectrum and cleaned map samples using the ILC method. We extend and improve the earlier reported Bayesian ILC method to analyze weak CMB B mode reconstruction by introducing noise bias corrections at two stages during the ILC weight estimation. By performing $200$ Monte Carlo simulations of the Bayesian ILC method, we find that our method can reconstruct the CMB signals and the joint posterior density accurately over large angular scales of the sky. We estimate Blackwell-Rao statistics of the marginal density of CMB B mode angular power spectrum and use them to estimate the joint density of scalar to tensor ratio $r$ and a lensing power spectrum amplitude $A^{\textrm{lens}}$. Using $200$ Monte Carlo simulations of the delensing approach, we find that our method can achieve an unbiased detection of the primordial gravitational wave signal $r$ with more than 8$σ$ significance for levels of $r \geqslant 0.01$.
