Find the twins: Evidence for a population of coalescing binary black holes with nearly equal-mass components

Yin-Jie Li, 2, ∗ Yuan-Zhu Wang, ∗ Shao-Peng Tang, 2 Qiang Yuan, 2 Yi-Zhong Fan, 2, † and Da-Ming Wei 2 Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, People’s Republic of China School of Astronomy and Space Science, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China (Dated: January 7, 2022)