论文标题
描述从重力波爆发的宇宙微波背景扰动的框架
Framework for describing perturbations to the cosmic microwave background from a gravitational wave burst with memory
论文作者
论文摘要
带有记忆（BWM）的引力波爆发可以在遥远的光源中产生可测量的，长寿命的频移和永久性偏转。这些扰动在天空中随着特征性的空间模式而变化，并在长时间的时间内缓慢发展。在这项工作中，我们开发了形式主义，可以用来描述BWM如何影响宇宙微波背景（CMB）中温度波动的空间模式。我们将注意力限制在平面重力波阵线上 - 这种假设极大地简化了必要的计算。使用CMB主要温度变化模式的玩具模型，我们证明了BWM可以将一定程度的球形谐波模式从某种程度的球形谐波模式混合到其他各种程度的模式，这些模式具有差异很大的$ L $值。换句话说，在任何角度尺度上，BWM诱导的对CMB的扰动都取决于所有角度尺度上CMB的不受干扰特征。本文开发的工具将极大地促进对BWM诱导的温度扰动的未来分析，这些温度扰动结合了CMB的所有重要物理。
Gravitational wave bursts with memory (BWMs) can generate measurable, long-lived frequency shifts and permanent angular deflections in distant sources of light. These perturbations vary across the sky with a characteristic spatial pattern and evolve slowly over long periods of time. In this work, we develop formalism that can be used to describe how a BWM influences the spatial pattern of temperature fluctuations in the cosmic microwave background (CMB). We limit our attention to planar gravitational wave fronts -- this assumption dramatically simplifies the necessary calculations. Using toy models of the CMB's primary temperature variation pattern, we demonstrate that a BWM can mix power from a spherical harmonic mode of a certain degree into modes of various other degrees with vastly different $l$ values. In other words, BWM-induced perturbations to the CMB at any angular scale depend in detail on the unperturbed character of the CMB on all angular scales. The tools developed herein will greatly facilitate future analyses of BWM-induced temperature perturbations that incorporate all of the important physics underlying the CMB.
