First detection of radio recombination lines of ions heavier than helium Xunchuan Liu, Tie Liu, Zhiqiang Shen, Paul F. Goldsmith, Neal J. Evans II, Sheng-Li Qin, Qiuyi Luo, Yu Cheng, Sheng-Yuan Liu, Fengyao Zhu et al. (25 more) A&A, 671 (2023) L1 Published online: 28 February 2023 DOI: 10.1051/0004-6361/202345904