Mon. Not. R. Astron. Soc., 499, 355-361 (2020/November-3)
On the magnetoionic environments of fast radio bursts.
WANG W.-Y., ZHANG B., CHEN X. and XU R.
Abstract (from CDS):
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+9.01–1.48 µG and 1.74+14.82–1.55 µG using two different methods, which is slightly larger but not inconsistent with the distribution of Galactic pulsars, 1.00+1.51–0.60 µG. 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 1.70 µG, 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.