Joint Bayesian estimation of tensor and lensing B modes in the power spectrum of CMB polarization data
Joint Bayesian estimation of tensor and lensing B modes in the power spectrum of CMB polarization data
复制标题
CMB 偏振数据功率谱中张量和透镜 B 模式的联合贝叶斯估计
DOI：
10.1093/mnras/stx3046
复制
发表时间：
2017
影响因子：
4.8
通讯作者：
I. Wehus
中科院分区：
文献类型：
--
作者：
M. Remazeilles;C. Dickinson;H. Eriksen;I. Wehus
我们研究了一个简单的贝叶斯拟合方法的性能，以纠正宇宙微波背景（CMB）的引力透镜效应的B-模式偏振的张量标量比的恢复概率分布。我们执行一个二维功率谱拟合的振幅的原始B-模式（张量标量比，$r$）和振幅的透镜B-模式（参数A_{透镜}$），连同估计的天体物理前景，包括同步辐射和热尘埃排放。使用这个贝叶斯框架，我们预测的能力，建议CMB空间使命LiteBIRD约束$r$现实的透镜和前景的贡献。本文计算了r和A_{透镜}$的联合后验分布，并通过对南极望远镜（SPT）测量的A_{透镜}$采用先验来改进后验分布。由于它适用于功率谱，这种方法不能减轻$r$的不确定性，这是由于E模式宇宙方差转移到B模式的透镜，不像标准的去透镜技术，在地图上执行。然而，该方法允许校正由透镜效应引起的r上的偏差，代价是由于参数空间的体积增加而导致的较大的不确定性。我们量化，张量标量比的不同值，偏置校正和增加的不确定性之间的权衡。对于LiteBIRD模拟，其中包括前景和透镜污染，我们发现，校正前景清洁CMB B-模式功率谱的透镜偏差，而不是透镜宇宙方差，仍然保证了$3\sigma$检测$r=5\times 10^{-3}$。当采用$A_{透镜}$上的当前SPT先验时，检测的重要性增加到$6\sigma$。
We investigate the performance of a simple Bayesian fitting approach to correct the cosmic microwave background (CMB) B-mode polarization for gravitational lensing effects in the recovered probability distribution of the tensor-to-scalar ratio. We perform a two-dimensional power spectrum fit of the amplitude of the primordial B-modes (tensor-to-scalar ratio, $r$) and the amplitude of the lensing B-modes (parameter $A_{lens}$), jointly with the estimation of the astrophysical foregrounds including both synchrotron and thermal dust emissions. Using this Bayesian framework, we forecast the ability of the proposed CMB space mission LiteBIRD to constrain $r$ in the presence of realistic lensing and foreground contributions. We compute the joint posterior distribution of $r$ and $A_{lens}$, which we improve by adopting a prior on $A_{lens}$ taken from the South Pole Telescope (SPT) measurement. As it applies to the power spectrum, this approach cannot mitigate the uncertainty on $r$ that is due to E-mode cosmic variance transferred to B-modes by lensing, unlike standard delensing techniques that are performed on maps. However, the method allows to correct for the bias on $r$ induced by lensing, at the expense of a larger uncertainty due to the increased volume of the parameter space. We quantify, for different values of the tensor-to-scalar ratio, the trade-off between bias correction and increase of uncertainty on $r$. For LiteBIRD simulations, which include foregrounds and lensing contamination, we find that correcting the foreground-cleaned CMB B-mode power spectrum for the lensing bias, not the lensing cosmic variance, still guarantees a $3\sigma$ detection of $r=5\times 10^{-3}$. The significance of the detection is increased to $6\sigma$ when the current SPT prior on $A_{lens}$ is adopted.
DOI：
10.17863/cam.43425
发表时间：
2016
期刊：
--
影响因子：
--
作者：
Aghanim N
通讯作者：
Aghanim N