FRBs and dark matter axions

TL;DR

This paper refines a model where fast radio bursts originate from neutron stars colliding with distorted dark matter axion stars, explaining narrowband signals and potential two-component bursts, consistent with observations.

Contribution

It introduces the effect of tidal forces on axion stars in the FRB progenitor model, showing the model remains consistent and explains specific FRB features.

Findings

Axion stars become elongated due to tidal forces near neutron stars.

FRBs are predicted to be narrowband signals.

Two-component FRBs may result from binary neutron star collisions.

Abstract

We have proposed a model of a progenitor of fast radio bursts (FRBs): The FRBs are emitted by electrons in atmospheres of neutron stars when neutron stars collide with dark matter axion stars. We reexamine the model by taking account of the tidal forces of the neutron stars. The axion stars are distorted by the forces so that they become like long sticks when they are close to the neutron stars. Although the tidal forces fairly distort the axion stars, our model is still consistent with present observations. We explain a distinctive feature of our model that the FRBs are not broadband, but narrowband. We also show that two-component FRBs may arise when the axion stars collide with binary neutron stars. FRBs would most frequently arise in centers of galaxies since the dark matter concentrates in the centers.