NS-WD Accretion

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Summary Table
Category Progenitor Type Energy Mechanism Emission Mechanism Counterparts References Brief Comments
LF Radio HF Radio Microwave Terahertz Optical/IR X-rays Gamma-rays Gravitational Waves Neutrinos
Accretion NS-WD Repeat Mag. reconnection Curv. Yes -- -- -- -- -- Yes, but unlikely detectable -- -- http://adsabs.harvard.edu/abs/2016ApJ...823L..28G None

Definitions: LF Radio (3 MHz to 3 GHz); HF Radio (3 GHz to 30 GHz); Microwave (30 to 300 GHz)

Model Description

This model considers the interaction between the bipolar magnetic fields of a NS and a magnetic white dwarf (WD) as a possible origin of repeating FRBs. As the WD exceeds its Roche lobe, the NS accretes the infalling matter. Upon their approach, the magnetized materials may trigger magnetic reconnection and emit curvature radiation. In a rapidly rotating neutron star, the angular momentum added by accretion is lost to gravitational radiation, but the mass transfer may be violent enough for the angular momentum of the WD to dominate over the gravitational radiation. In this case, the WD is kicked away from the NS, and the process of accretion, and thus magnetic reconnection, may repeat. The timescale of emission is assumed to be the same as that of magnetic reconnection, and the time interval between adjacent bursts is derived from its relationship to the mass transferred by the burst.

Observational Constraints

Gamma-ray emission from synchrotron radiation is unlikely detectable.

Consistency with Observations

The time interval between bursts of FRB 121102 is consistent with this model.