FRB 200428: An Impact between an Asteroid and a Magnetar
Jin-Jun Geng, Bing Li, Long-Biao Li, S. L. Xiong, R. Kuiper, Yong-Feng Huang
Abstract
Abstract A fast radio burst (FRB) was recently detected to be associated with a hard X-ray burst from the Galactic magnetar SGR 1935+2154. Scenarios involving magnetars for FRBs are hence highly favored. In this work, we suggest that the impact between an asteroid and a magnetar could explain such a detection. According to our calculations, an asteroid of mass 10 20 g will be disrupted at a distance of 7 × 10 9 cm when approaching the magnetar. The accreted material will flow along the magnetic field lines from the Alfvén radius ∼10 7 cm. After falling onto the magnetar’s surface, an instant accretion column will be formed, producing a Comptonized X-ray burst and an FRB in the magnetosphere. We show that all the observational features of FRB 200428 could be interpreted self-consistently in this scenario. We predict quasi-periodic oscillations in this specific X-ray burst, which can serve as an independent observational test.