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 1020 g will be disrupted at a distance of 7×109 cm when approaching the magnetar. The accreted material will flow along the magnetic field lines from the Alfv\'en radius ∼107 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.
@article{arxiv.2006.04601,
title = {FRB 200428: an Impact between an Asteroid and a Magnetar},
author = {Jin-Jun Geng and Bing Li and Long-Biao Li and Shao-Lin Xiong and Rolf Kuiper and Yong-Feng Huang},
journal= {arXiv preprint arXiv:2006.04601},
year = {2020}
}
Comments
5 pages, 1 figure. References updated, accepted by ApJL