Quasi-periodic oscillations of the X-ray burst from the magnetar SGR J1935+2154 and associated with the fast radio burst FRB 200428

TL;DR

This paper reports the detection of a strong 40 Hz quasi-periodic oscillation in an X-ray burst from the magnetar SGR J1935+2154, associated with FRB 200428, providing evidence linking magnetar oscillations to fast radio bursts.

Contribution

The study presents the first strong detection of a QPO in a magnetar burst associated with an FRB, highlighting the potential connection between neutron star oscillations and FRB phenomena.

Findings

Detected a 40 Hz QPO with 3.4 sigma significance.

X-ray spikes coincided with FRB pulses and QPO peaks.

Results suggest some FRBs originate from neutron star oscillations.

Abstract

The origin(s) and mechanism(s) of fast radio bursts (FRBs), which are short radio pulses from cosmological distances, have remained a major puzzle since their discovery. We report a strong Quasi-Periodic Oscillation(QPO) of 40 Hz in the X-ray burst from the magnetar SGR J1935+2154 and associated with FRB 200428, significantly detected with the Hard X-ray Modulation Telescope (Insight-HXMT) and also hinted by the Konus-Wind data. QPOs from magnetar bursts have only been rarely detected; our 3.4 sigma (p-value is 2.9e-4) detection of the QPO reported here reveals the strongest QPO signal observed from magnetars (except in some very rare giant flares), making this X-ray burst unique among magnetar bursts. The two X-ray spikes coinciding with the two FRB pulses are also among the peaks of the QPO. Our results suggest that at least some FRBs are related to strong oscillation processes of neutron stars. We also show that we may overestimate the significance of the QPO signal and underestimate the errors of QPO parameters if QPO exists only in a fraction of the time series of a X-ray burst which we use to calculate the Leahy-normalized periodogram.