The Galactic neutron star population I - an extragalactic view of the Milky Way and the implications for fast radio bursts

TL;DR

This study compares the spatial distribution of Galactic neutron stars with extragalactic transients, finding that fast radio bursts are most consistent with being produced by neutron stars in the Milky Way.

Contribution

The paper introduces a novel extragalactic perspective by mapping the Milky Way's neutron star populations and comparing their distributions to those of transients like FRBs.

Findings

FRBs' spatial distribution closely matches that of Galactic neutron stars.

Galactic neutron stars are more consistent with FRB locations than other transients.

Results support models linking FRBs to young neutron stars or neutron star binaries.

Abstract

A key tool astronomers have to investigate the nature of extragalactic transients is their position on their host galaxies. Galactocentric offsets, enclosed fluxes and the fraction of light statistic are widely used at different wavelengths to help infer the nature of transient progenitors. Motivated by the proposed link between magnetars and fast radio bursts (FRBs), we create a face-on image of the Milky Way using best estimates of its size, structure and colour. We place Galactic magnetars, pulsars, low mass and high mass X-ray binaries on this image, using the available distance information. Galactocentric offsets, enclosed fluxes and fraction of light distributions for these systems are compared to extragalactic transient samples. We find that FRBs follow the distributions for Galactic neutron stars closest, with 24 (75 per cent) of the Anderson-Darling tests we perform having a p-value greater than 0.05. This suggests that FRBs are located on their hosts in a manner consistent with Galactic neutron stars on the Milky Way's light, although we cannot determine which specific neutron star population is the best match. The Galactic distributions are consistent with other extragalactic transients much less often across the range of comparisons made, with type Ia SNe in second place, at only 33 per cent of tests exceeding 0.05. Overall, our results provide further support for FRB models invoking isolated young neutron stars, or binaries containing a neutron star.