Emission Properties of Periodic Fast Radio Bursts from the Motion of Magnetars: Testing Dynamical Models
- Creators
- Li, Dongzi
- Zanazzi, J. J.
Abstract
Recent observations of the periodic fast radio burst source 180916.J0158+65 (FRB 180916) find small linear polarization position angle swings during and between bursts, with a burst activity window that becomes both narrower and earlier at higher frequencies. Although the observed chromatic activity window disfavors models of periodicity in FRB 180916 driven solely by the occultation of a neutron star by the optically thick wind from a stellar companion, the connection to theories where periodicity arises from the motion of a bursting magnetar remains unclear. In this Letter, we show how altitude-dependent radio emission from a magnetar, with bursts emitted from regions that are asymmetric with respect to the magnetic dipole axis, can lead to burst activity windows and polarization consistent with the recent observations. In particular, the fact that bursts arrive systematically earlier at higher frequencies disfavors theories where the FRB periodicity arises from forced precession of a magnetar by a companion or fallback disk, but is consistent with theories where periodicity originates from a slowly rotating or freely precessing magnetar. Several observational tests are proposed to verify/differentiate between the remaining theories, and pin down which theory explains the periodicity in FRB 180916.
Additional Information
© 2021. The American Astronomical Society. Received 2021 January 14; revised 2021 February 24; accepted 2021 March 1; published 2021 March 15. D.Z.L. acknowledges the discussion with Liam Connor and Vikram Ravi. J.Z. was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), [funding reference #CITA 490888-16].Attached Files
Published - Li_2021_ApJL_909_L25.pdf
Accepted Version - 2101.05836.pdf
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Additional details
- Eprint ID
- 108647
- Resolver ID
- CaltechAUTHORS:20210407-144128979
- CITA 490888-16
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Created
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2021-04-07Created from EPrint's datestamp field
- Updated
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2021-04-07Created from EPrint's last_modified field