论文标题

极化信号的高精度建模:矩膨胀方法推广到自旋2场

High precision modeling of polarized signals: Moment expansion method generalized to spin-2 fields

论文作者

Vacher, Léo, Chluba, Jens, Aumont, Jonathan, Rotti, Aditya, Montier, Ludovic

论文摘要

前景的建模和去除对使用宇宙微波背景(CMB)搜索通货膨胀的信号构成了重大挑战。特别是,CMB前景的建模包括各种空间平均效应引入了多种并发症,这些并发症必须在即将进行的分析中考虑到。在这项工作中,我们将强度矩膨胀的概括介绍到线性极化的自旋2场:自旋力膨胀。在此框架内,矩成为Spin-2对象,与基础光谱参数和极化角度分布函数直接相关。在获得极化建模所需的表达式时,我们强调了与强度力矩方法的相似性和差异。具有频率的复合平面中的旋转旋转自然来自信号既包含光谱参数和极化角变化的第一阶矩。额外的依赖项会以更高的阶段引入,我们演示了如何通过几个说明性示例来考虑这些依赖项。我们对极化信号的新建模显示,是建模极化角度依赖性的强大工具。因此,它可以立即应用于许多天体物理情况。

The modeling and removal of foregrounds poses a major challenge to searches for signals from inflation using the cosmic microwave background (CMB). In particular, the modeling of CMB foregrounds including various spatial averaging effects introduces multiple complications that will have to be accounted for in upcoming analyses. In this work, we introduce the generalization of the intensity moment expansion to the spin-2 field of linear polarization: the spin-moment expansion. Within this framework, moments become spin-2 objects that are directly related to the underlying spectral parameters and polarization angle distribution functions. In obtaining the required expressions for the polarization modeling, we highlight the similarities and differences with the intensity moment methods. A spinor rotation in the complex plane with frequency naturally arises from the first order moment when the signal contains both spectral parameters and polarization angle variations. Additional dependencies are introduced at higher order, and we demonstrate how these can be accounted with several illustrative examples. Our new modeling of the polarized signals reveals to be a powerful tool to model the frequency dependence of the polarization angle. As such, it can be immediately applied to numerous astrophysical situations.

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