Testing Models of Periodically Modulated FRB Activity

Understand

The activity of the repeating FRB 20180916B is periodically modulated with a period of 16.3 days, and FRB 121102 may be similarly modulated with a period of about 160 days.

• In some models of this modulation the period derivative is insensitive to the uncertain parameters; these models can be tested by measurement of or bounds on the derivative.
• In other models values of the uncertain parameters can be constrained.
• Periodic modulation of aperiodic bursting activity may result from emission by a narrow beam wandering within a cone or funnel along the axis of a precessing disc, such as the accretion discs in X-ray binaries.