Origin of periodic activity windows in repeating FRB sources
In plain words
Some repeating sources are active only in windows that recur every 16 or about 160 days, and the clock behind this is unknown.
Precise statement
FRB 20180916B shows activity windows with period $\sim 16.3\,\mathrm{days}$ and FRB 20121102A a candidate $\sim 160\,\mathrm{day}$ period. Identify the mechanism (binary orbit with a massive companion wind, free precession of a magnetar, or ultra-slow rotation) by predicting frequency-dependent window drift and phase-dependent dispersion measure, rotation measure and polarization. Answer: the mechanism consistent with all phase-resolved data.
What would settle it
Phase-resolved monitoring of rotation measure, dispersion measure and polarization over many cycles, testing binary-orbit predictions against precession predictions of period drift.
Related problems
- Special case of Which astrophysical objects produce fast radio bursts?