Fast radio bursts (FRBs) are short, bright cosmic flashes in the radio spec­trum. Recently, a unique FRB (FRB 200428) and its nonthermal X-ray counterpart were detected simultaneously from a galactic magnetar named SGR 1935+2154, confirming that FRBs may emerge from magnetars. However, the physical origin of the radio and the X-ray burst remains uncertain. Quantum electrodynamic (QED) effects play a cru­cial role in particle acceleration and photon emissions in magnetars since the magnetic field near magnetars is 10 trillion times stronger than that of the Sun. The research team led by Prof. Bin Qiao from Peking University and Prof. Xuefeng Wu from the Purple Mountain Observatory proposed a precise and dedicated model for the origin of FRB-associated X-ray bursts around magnetars to explore the generation mechanism of such X-ray bursts. They believe the FRB-associated X-ray bursts may result from QED reconnections in the magnetar magnetosphere. For the first time, the team performed numerical simulations incorporating small-scale magnetic reconnections, large-scale photon emissions, and multiple Compton scattering processes. Soft X-ray photons undergo up­scattering by the electrons accelerated through the reconnections, generating observed hard X-ray photons. The simulation results are consistent with the temporal and spectral features determined from the observational data of Insight-Hard X-ray Modulation Telescope (Insight-HXMT). This cover image is an artist’s impression of the proposed origin model for the FRB 200428-associated X-ray burst (see the short communication by Yu Xie et al. on page 1857).

Fast radio bursts (FRBs) are short, bright cosmic flashes in the radio spec­trum. Recently, a unique FRB (FRB 200428) and its nonthermal X-ray counterpart were detected simultaneously from a galactic magnetar named SGR 1935+2154, confirming that FRBs may emerge from magnetars. However, the physical origin of the radio and the X-ray burst remains uncertain. Quantum electrodynamic (QED) effects play a cru­cial role in particle acceleration and photon emissions in magnetars since the magnetic field near magnetars is 10 trillion times stronger than that of the Sun. The research team led by Prof. Bin Qiao from Peking University and Prof. Xuefeng Wu from the Purple Mountain Observatory proposed a precise and dedicated model for the origin of FRB-associated X-ray bursts around magnetars to explore the generation mechanism of such X-ray bursts. They believe the FRB-associated X-ray bursts may result from QED reconnections in the magnetar magnetosphere. For the first time, the team performed numerical simulations incorporating small-scale magnetic reconnections, large-scale photon emissions, and multiple Compton scattering processes. Soft X-ray photons undergo up­scattering by the electrons accelerated through the reconnections, generating observed hard X-ray photons. The simulation results are consistent with the temporal and spectral features determined from the observational data of Insight-Hard X-ray Modulation Telescope (Insight-HXMT). This cover image is an artist’s impression of the proposed origin model for the FRB 200428-associated X-ray burst (see the short communication by Yu Xie et al. on page 1857).