Radius-to-frequency Mapping and FRB Frequency Drifts

Journal Article · 31 January 2020 · The Astrophysical Journal (Online)

DOI: https://doi.org/10.3847/1538-4357/ab55de · OSTI ID:1802960

Lyutikov, Maxim  ^[1]

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1. Purdue Univ., West Lafayette, IN (United States). Dept. of Physics and Astronomy; Purdue University

We build a model of radius-to-frequency mapping in magnetospheres of neutron stars and apply it to frequency drifts observed in fast radio bursts (FRBs). We assume that an emission patch propagates along the dipolar magnetic field lines, producing coherent emission with frequency, direction, and polarization defined by the local magnetic field. The observed temporal evolution of the frequency depends on the relativistic effects of time contraction and the curvature of the magnetic field lines. The model generically produces linear scaling of the drift rate, $$\dot{\omega}$$ ∝-$${\omega}$$, matching both numerically and parametrically the rates observed in FBRs; a more complicated behavior of $$\dot{\omega}$$ is also possible. Fast rotating magnetospheres produce higher drifts rates for similar viewing parameters than the slowly rotating ones. In the case of repeaters, the same source may show variable drift patterns depending on the observing phase. We expect rotational of polarization position angle through a burst, though by smaller amount than in radio pulsars. All of these findings compare favorably with properties of FBRs, strengthening their possible loci in the magnetospheres of neutron stars.

• Research Organization: Purdue Univ., West Lafayette, IN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC0016369
• OSTI ID: 1802960
• Journal Information: The Astrophysical Journal (Online), Journal Name: The Astrophysical Journal (Online) Journal Issue: 2 Vol. 889; ISSN 1538-4357
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English