Many of the satellites of galactic-mass systems such as the Miky Way, Andromeda and Centaurus A show evidence of coherent motions to a larger extent than most of the systems predicted by the standard cosmological model. It is an open question if correlations in satellite orbits are present in systems of different masses. Here we report an analysis of the kinematics of satellite galaxies around massive galaxy groups. Unlike what is seen in Milky Way analogues, we find an excess of diametrically opposed pairs of satellites that have line-of-sight velocity offsets from the central galaxy of the same sign. This corresponds to a 6.0σ (P value = 9.9 × 10⁻¹⁰) detection of non-random satellite motions. Such excess is predicted by up-to-date cosmological simulations but the magnitude of the effect is considerably lower than in observations. The observational data is discrepant at the 4.1σ and 3.6σ level with the expectations of the Millennium and the Illustris TNG300 cosmological simulations, potentially indicating that massive galaxy groups assembled later in the real Universe. The detection of velocity correlations of satellite galaxies and tension with theoretical predictions is robust against changes in sample selection. Using the largest sample to date, our findings demonstrate that the motions of satellite galaxies represent a challenge to the current cosmological model.

许多星系质量系统的卫星，如米基路、仙女座和半人马座 A，都显示出比标准宇宙学模型预测的大多数系统更大程度的相干运动证据。卫星轨道的相关性是否存在于不同质量的系统中是一个悬而未决的问题。在这里，我们报告了对大质量星系团周围卫星星系运动学的分析。与银河系类似物不同的是，我们发现了过多的完全相反的卫星对，它们的视线速度与相同符号的中央星系有偏移。这对应于非随机卫星运动的6.0 σ（P值 = 9.9 × 10 ^{-10 ）检测。}最新的宇宙学模拟预测了这种过量现象，但其影响程度远低于观测结果。观测数据在 4.1 σ和 3.6 σ水平上与 Millennium 和 Illustris TNG300 宇宙学模拟的预期存在差异，这可能表明巨大的星系团在真实宇宙中后来聚集。卫星星系的速度相关性和张力与理论预测的检测对于样本选择的变化是稳健的。使用迄今为止最大的样本，我们的研究结果表明，卫星星系的运动对当前的宇宙学模型构成了挑战。