FRB 200428: an Impact between an Asteroid and a Magnetar

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 $7\times 10^9$ cm when approaching the magnetar. The accreted material will flow along the magnetic field lines from the Alfvén radius $\sim 10^7$ 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.

5 pages, 1 figure. References updated, accepted by ApJL

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Cited by in corpus (8)

• The Physics of Fast Radio Bursts
• Periodic Activities of Repeating Fast Radio Bursts from Be/X-ray Binary Systems
• Double-peaked Pulse Profile of FRB 200428: Synchrotron Maser Emission from Magnetized Shocks Encountering a Density Jump
• 81 New Candidate Fast Radio Bursts in Parkes Archive
• Earth-mass primordial black hole mergers as sources for non-repeating FRBs
• The radio/X-ray burst from SGR 1935+2154: radiation mechanisms and the possible QPOs
• Do the periodic activities of repeating fast radio bursts represent the spins of neutron stars?
• Understanding FRB 200428 in the synchrotron maser shock model: consistency and possible challenge