A great deal of attention has been given to the so-called Cold Spot in maps of the cosmic microwave background (CMB) temperature. We present a similar analysis, searching for extremal spots in the CMB lensing convergence and lensing potential maps from the Planck 2018 data release. We perform a multi-scale and multi-filter analysis using the first three members of the Mexican-hat wavelet family to search for extremal features of different shapes and sizes. Although an initial analysis appears to show the existence of some extremal spots at scales below about 5, we conclude, after marginalising over all scales and filters, that no significant features are detected in the lensing maps. We conclude that in terms of maxima and minima of various sizes, the lensing data have similar statistical properties to Gaussian simulations.

宇宙微波背景 (CMB) 温度图中的所谓冷点受到了极大的关注。我们提出了类似的分析，在 CMB 透镜收敛和普朗克透镜势图中寻找极值点2018年数据发布。我们使用墨西哥帽小波家族的前三个成员执行多尺度和多滤波器分析，以搜索不同形状和大小的极值特征。尽管初步分析似乎表明在低于 5 的尺度下存在一些极值点，但我们得出结论，在对所有尺度和过滤器进行边缘化后，在透镜图中未检测到显着特征。我们得出结论，就各种大小的最大值和最小值而言，透镜数据具有与高斯模拟相似的统计特性。