Title

On the Magnetoionic Environments of Fast Radio Bursts

Document Type

Article

Publication Date

9-7-2020

Publication Title

Monthly Notices of the Royal Astronomical Society

Volume

499

Issue

1

First page number:

355

Last page number:

361

Abstract

Observations of the Faraday rotation measure, combined with the dispersion measure, can be used to infer the magnetoionic environment of a radio source. We investigate the magnetoionic environments of fast radio bursts (FRBs) by deriving their estimated average magnetic field strengths along the line of sight 〈B∥〉 in their host galaxies and comparing them with those of Galactic pulsars and magnetars. We find that for those FRBs with RM measurements, the mean 〈B∥〉 are 1.77+9.01−1.48μG and 1.74+14.82−1.55μG using two different methods, which is slightly larger but not inconsistent with the distribution of Galactic pulsars, 1.00+1.51−0.60μG⁠. Only six Galactic magnetars have estimated 〈B∥〉. Excluding PSR J1745–2900 that has an anomalously high value due to its proximity with the Galactic Centre, the other five sources have a mean value of 1.70μG⁠, which is statistically consistent with the 〈B∥〉 distributions of both Galactic pulsars and FRBs. There is no apparent trend of evolution of magnetar 〈B∥〉 as a function of age or surface magnetic field strength. Galactic pulsars and magnetars close to the Galactic Centre have relatively larger 〈B∥〉 values than other pulsars/magnetars. We discuss the implications of these results for the magnetoionic environments of FRB 121102 within the context of magnetar model and the model invoking a supermassive black hole, and for the origin of FRBs in general.

Keywords

Stars: Neutron; Pulsars: General; Fast radio bursts

Disciplines

Stars, Interstellar Medium and the Galaxy

Language

English

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