On the magnetoionic environments of fast radio bursts

Wei-Yang Wang; Bing Zhang; Xuelei Chen; Renxin Xu

doi:10.1093/mnras/staa2693

paper

On the magnetoionic environments of fast radio bursts

arXiv:2009.00790 · doi:10.1093/mnras/staa2693

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 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 $⟨ B_{∥} ⟩$ is $1.7 7_{- 1.48}^{+ 9.01} μ G$ and $1.7 4_{- 1.55}^{+ 14.82} μ G$ using two different methods, which is slightly larger but not inconsistent with the distribution of Galactic pulsars, $1.0 0_{- 0.60}^{+ 1.51} μ G$ . 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 three sources have a mean value of $1.70 μ G$ , 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.

arXiv comment8 pages, 3 figures, MNRAS accepted

On the magnetoionic environments of fast radio bursts

Abstract

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