Repeating Fast Radio Bursts from Highly Magnetized Pulsars Travelling through Asteroid Belts

TL;DR

This paper proposes a model where highly magnetized pulsars passing through asteroid belts produce repeating fast radio bursts via electron acceleration and coherent curvature radiation, explaining observed properties of FRB 121102.

Contribution

The study introduces a novel pulsar-asteroid impact model for repeating FRBs, linking astrophysical phenomena to observed burst characteristics and suggesting testable predictions.

Findings

Model explains duration, luminosity, and repetition rate of FRB 121102.

Electrons torn from asteroids produce coherent curvature radiation.

Predicted occurrence rate of repeating FRBs is testable in the near future.

Abstract

Very recently Spitler et al. (2016) and Scholz et al. (2016) reported their detections of sixteen additional bright bursts from the direction of the fast radio burst (FRB) 121102. This repeating FRB is inconsistent with all the catastrophic event models put forward previously for hypothetically non-repeating FRBs. Here we propose a different model, in which highly magnetized pulsars travel through asteroid belts of other stars. We show that a repeating FRB could originate from such a pulsar encountering lots of asteroids in the belt. During each pulsar-asteroid impact, an electric field induced outside the asteroid has such a large component parallel to the stellar magnetic field that electrons are torn off the asteroidal surface and accelerated to ultra-relativistic energies instantaneously. Subsequent movement of these electrons along magnetic field lines will cause coherent curvature radiation, which can account for all the properties of an FRB. In addition, this model can self-consistently explain the typical duration, luminosity, and repetitive rate of the seventeen bursts of FRB 121102. The predicted occurrence rate of repeating FRB sources may imply that our model would be testable in the next few years.