A model of neutron-star--white-dwarf collision for fast radio bursts

TL;DR

This paper proposes a neutron-star--white-dwarf collision model as a potential explanation for fast radio bursts, deriving relations between observable properties and comparing them with limited data, suggesting correlations consistent with the model.

Contribution

It introduces a novel collision-based model for FRBs and derives testable relations among flux, duration, and dispersion measure, aligning with observed trends.

Findings

Tentative inverse-square correlation between flux density and DM excess.

Possible correlation between FRB duration and DM excess.

Shorter bursts tend to be brighter, consistent with the model.

Abstract

Fast radio bursts (FRBs) with unknown origin emit a huge luminosity (about 1 Jy at 1 GHz) with a duration of milliseconds or less at extragalactic distances estimated from their large dispersion measure (DM). We propose herein a scenario for a collision between a neutron star (NS) and a white dwarf (WD) as the progenitor of the FRBs by considering the burst duration scaling to the collision time and the radio luminosity proportional to the kinetic energy of the collision. The relations among the observed flux density, pulse width, and the DM are derived from the model and compared with the statistical results from the observed FRBs. Although the sample is quite small, we tentatively report a nearly inverse-square correlation between the observed peak flux density and the DM excess, which is an consequence of the assumption that the DM excess (i.e. that not due to our Galaxy) is dominated by the intergalactic medium. We also tentatively note a correlation among the duration of the FRB and the DM excess (possibly interpreted as due to the broadening of the signal in the intergalactic medium) and a correlation among the duration of the FRB and the flux density (shorter burst should be brighter), both roughly in agreement with the proposed model.