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Searching for Periodicity in FRB 20240114A

J. I. Katz

TL;DR

This study tests the magnetar-rotation hypothesis for FRB periodicity in FRB 20240114A by applying a periodogram to 11,553 bursts (including 3,196 within a 15628 s window) and by allowing for a possible spin-down rate $\dot{\omega}$. No significant periodic signal emerges, even when extending the search to frequencies up to $\sim100$ Hz and scanning $\dot{\omega} \in [-10^{-6},10^{-6}]$ s$^{-2}$, yielding a modulation-detection threshold of roughly $15\%$ for a 1 Hz modulation. Under a dipole-spindown framework with age $A_y\gtrsim1$ year, the non-detection imposes $\mu_{33} \leq 0.57 A_y^{-3/2}$, suggesting that either the emission is geometrically arranged to minimize detectable modulation or magnetar spin-down and beaming permit configurations where overall modulation remains small. The results constrain simple rotational modulation in FRB activity, indicating that magnetar FRB models must account for potential azimuthal symmetry, axis alignment, or alternative beaming geometries to reconcile with null periodicity evidence.

Abstract

FRB 20240114A is extraordinarily active, and therefore presents an opportunity to search for the periodicity predicted by magnetar models of Fast Radio Bursts (FRB). Zhang, et al. (2025) observed 11,553 bursts, including 3196 on MJD 60381 (March 12, 2024). We find no significant peak in the periodogram of those bursts, which occur within 15628 s, short enough that even with a characteristic slowing age of 1 year a signal with period $\ge 0.1\,$s it would not significantly dephase within the observation. Introducing modulation artificially shows that an amplitude of 0.15 would have been detected robustly.

Searching for Periodicity in FRB 20240114A

TL;DR

This study tests the magnetar-rotation hypothesis for FRB periodicity in FRB 20240114A by applying a periodogram to 11,553 bursts (including 3,196 within a 15628 s window) and by allowing for a possible spin-down rate . No significant periodic signal emerges, even when extending the search to frequencies up to Hz and scanning s, yielding a modulation-detection threshold of roughly for a 1 Hz modulation. Under a dipole-spindown framework with age year, the non-detection imposes , suggesting that either the emission is geometrically arranged to minimize detectable modulation or magnetar spin-down and beaming permit configurations where overall modulation remains small. The results constrain simple rotational modulation in FRB activity, indicating that magnetar FRB models must account for potential azimuthal symmetry, axis alignment, or alternative beaming geometries to reconcile with null periodicity evidence.

Abstract

FRB 20240114A is extraordinarily active, and therefore presents an opportunity to search for the periodicity predicted by magnetar models of Fast Radio Bursts (FRB). Zhang, et al. (2025) observed 11,553 bursts, including 3196 on MJD 60381 (March 12, 2024). We find no significant peak in the periodogram of those bursts, which occur within 15628 s, short enough that even with a characteristic slowing age of 1 year a signal with period s it would not significantly dephase within the observation. Introducing modulation artificially shows that an amplitude of 0.15 would have been detected robustly.
Paper Structure (10 sections, 5 equations, 2 figures)

This paper contains 10 sections, 5 equations, 2 figures.

Table of Contents

  1. Introduction
  2. Types of periodicity
  3. RRAT periodicity
  4. Periodic Modulation of Activity
  5. Parameters and Phase Drift
  6. Results
  7. Frequency Derivative
  8. Sensitivity
  9. Periodicity?
  10. Conclusion

Figures (2)

  • Figure 1: Periodogram of 3196 bursts of FRB 20240114A in a 15628 s observation March 12, 2024 (MJD 60381), data from Z25. Extension of the calculation to frequencies of 100 Hz (implying a neutron star with $\mu_{33} \ll 1$ unless its age is $\ll 1\,$y) produced no higher peaks than shown here.
  • Figure 2: Distribution of amplitudes of the periodogram of the March 12, 2024 observation Z25 of FRB2024014A, with stochastic modulation of various amplitudes $M$ imposed. A 15% modulation of the event rate is readily detected but a 10% modulation cannot be.