Signatures of peculiar velocities in the cosmic microwave background

星系团特有速度场的统计（即，与宇宙膨胀无关的运动）对暗物质、暗能量和引力理论的性质有很大的信息量。目前，大尺度上的奇特速度测量仅限于星系团的视线分量，使得我们无法获得速度场中的大部分可用信息。 通过两种效应可以追踪到尚未探测到的宇宙微波背景辐射的横向分量：（i）在宇宙微波背景辐射温度下的Birkinshaw-Gull（BG）效应，以及（ii）在宇宙微波背景辐射极化中的动力学Sunyaev-Zeldocivh（kSZ）效应。在这项研究中，我们作出了现实的评估，这些信号的可探测性与不久的将来的CMB实验，并探讨利用这些信号的统计宇宙学的可能性。PI将为K-12学生开发一种创造性的教育产品，以提高对物理学和宇宙学的认识和兴趣，特别是星系团和结构形成的物理学。K-12教师将接受培训，通过南加州大学的学校家庭利用现有的关系使用这一教育产品。开发的材料也将提供给所有愿意下载和使用它的教育工作者在线。BG和kSZ效应的幅度相对于主CMB各向异性和当前仪器噪声水平是次显性的。除此之外，这些信号可能会与来自星系团内外的其他辐射、引力透镜效应以及星系团物理描述的不确定性混淆。因此，几乎不可能观察到单个对象的这些影响。然而，它仍然是可能的，以实现一个成功的检测，他们采用新的统计方法在数据分析。一个例子是使用成对的统计估计，已被证明显着增加检测信噪比。在整个项目中，我们将研究在不久的将来使用下一代CMB调查测量这些信号的可能性。我们将提供预测分析，通过半分析和数值模拟集群，并为此目的引入适当的地图过滤技术和新的统计工具。目前的普遍兴趣，在生产更大和更深的CMB调查与改进的强度和偏振灵敏度，使这是一个适当的时间，以进一步研究的特殊速度和检查其宇宙学的implications.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

The statistics of the peculiar velocity field of galaxy clusters (i.e., motions not related to expansion of the universe) are highly informative about the nature of dark matter, dark energy, and the theory of gravity. Currently, peculiar velocity measurements on large scales are limited to only the line-of-sight components of clusters, leaving most of the available information in the velocity field inaccessible to us. The yet-undetected transverse components can be traced through the cosmic microwave background (CMB) via two effects: (i) the Birkinshaw-Gull (BG) effect in CMB temperature, and (ii) the Kinetic Sunyaev-Zeldocivh (kSZ) effect in CMB polarization. In this research, we make a realistic assessment of the detectability of these signals with the near future CMB experiments, and also investigate the possibility of exploiting the statistics of these signals for cosmology. The PI will develop a creative educational product for K-12 students to promote awareness of and interest in physics and cosmology, in particular the physics of galaxy clusters and structure formation. K-12 teachers will be trained to use this educational product leveraging on existing relationships via the USC family of schools. The developed material will also be available online for all educators willing to download and use it. The amplitude of both BG and kSZ effects are subdominant with respect to the primary CMB anisotropies and current instrumental noise levels. Aside from this, the signals can be confused with other emissions from within and outside the clusters, gravitational lensing effects, and uncertainties in clusters' physical description. Therefore, it is almost impossible to observe these effects for individual objects. Nevertheless, it is still possible to achieve a successful detection of them by employing novel statistical methods in the analysis of data. One example is to use pairwise statistical estimators which have been shown to significantly increase the detection signal-to-noise ratio. Throughout this project we will investigate the possibility of measuring these signals in the near future using the next generation of CMB surveys. We will provide forecast analyses through semi-analytical and numerical simulations of clusters and introduce proper map-filtering techniques and new statistical tools for this purpose. The current general interest in producing larger and deeper CMB surveys with improved intensity and polarization sensitivities makes this an appropriate time to further the study of peculiar velocities and inspect their cosmological implications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.