The detection of X-ray or gamma-ray spectral lines in gamma-ray bursts (GRBs) is rare. Here, the authors report a probable evidence of a narrow emission feature at about 2.1 mega-electron volts (MeV) in the spectrum of GRB 221023A, which represents the second event following GRB 221009A with a narrow emission feature in the MeV energy range.
- Lu-Yao Jiang
- Yun Wang
- Zhi-Ping Jin