Squared temperature-temperature power spectrum as a probe of the CMB bispectrum
Squared temperature-temperature power spectrum as a probe of the CMB bispectrum
复制标题
平方温度-温度功率谱作为 CMB 双谱的探针
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
A. Cooray
中科院分区：
文献类型：
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作者：
A. Cooray
现在众所周知，与某些次级效应相关的模式耦合效应会在宇宙微波背景（CMB）温度各向异性中产生更高阶的相关性，超出两点函数。为了在三点水平上提取这种非高斯信号，我们建议采用角功率谱形式的两点统计，涉及温度平方和温度各向异性之间的相关性。该功率谱包含来自双谱的压缩信息，并且可以使用与通常的温度-温度各向异性功率谱测量所考虑的相同技术在数据中轻松测量。我们研究了所提出的功率谱，该功率谱是由与宇宙微波背景中的引力透镜角偏转和大规模压力波动引起的 Sunyaev-Zel’dovich (SZ) 效应相关的相关性生成的非高斯信号产生的。使用普朗克频率清理的 CMB 和 SZ 图，CMB2-SZ 功率谱提供了透镜角偏转和 SZ 效应之间互功率的直接估计。通过对平方 CMB 图应用最佳滤波器，所提出的统计量允许人们从透镜-SZ 双谱中获取所有信息。透镜-SZ互相关的观测测量有助于理解大尺度结构压力与暗物质涨落之间的关系。
It is now well known that mode-coupling effects associated with certain secondary effects generate higher order correlations in cosmic microwave background (CMB) temperature anisotropies, beyond the two-point function. In order to extract such a non-Gaussian signal at the three-point level, we suggest a two-point statistic in the form of an angular power spectrum involving correlations between squared temperature and temperature anisotropies. This power spectrum contains compressed information from the bispectrum and can be easily measured in data with the same techniques that have been considered for the measurement of the usual temperature-temperature anisotropy power spectrum. We study the proposed power spectrum resulting from the non-Gaussian signal generated by correlations involved with gravitational lensing angular deflections in CMB and the Sunyaev-Zel’dovich (SZ) effect due to large scale pressure fluctuations. Using the Planck frequency cleaned CMB and SZ maps, the CMB2-SZ power spectrum provides a direct estimate of the cross-power between lensing angular deflections and the SZ effect. Through an optimal filter applied to the squared CMB map, the proposed statistic allows one to obtain all information from the lensing-SZ bispectrum. The observational measurement of the lensing-SZ cross-correlation is useful to understand the relation between large scale structure pressure and dark matter fluctuations.