SIMBAD references

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.