Detection of a Millisecond Periodicity in BATSE Short Gamma-Ray Bursts

TL;DR

This paper reports the detection of a millisecond periodicity at 1100 Hz in a short gamma-ray burst, supporting the idea that such periodicities can originate from merger-driven central engines like nascent magnetars.

Contribution

It presents the first significant detection of a millisecond periodicity in a short GRB using BATSE data, expanding understanding of GRB central engine dynamics.

Findings

Detected a 1100 Hz periodicity in GRB 960616

Placed an upper limit of 8% on energy modulation fraction

Supports the merger-driven scenario for millisecond periodicities

Abstract

Coherent oscillations at kilohertz frequencies have recently been detected in a small number of gamma-ray bursts (GRBs), suggesting quasi-periodic dynamics in their central engines. A prominent example is GRB~230307A, which exhibited a brief, highly coherent, energy-dependent periodic signal interpreted as the possible spin signature of a nascent millisecond magnetar formed after a compact binary merger. Motivated by these developments, we conducted a comprehensive search for similar signals, accounting for both temporal and spectral dependencies, in 532 short GRBs with time-tagged event data recorded by the Burst and Transient Source Experiment (BATSE) onboard the \textit{Compton Gamma-Ray Observatory}. Within this sample, we identify a single statistically significant case: GRB~960616 (BATSE trigger~5502), in which the $\sim$30~ms main emission episode is coherently modulated at 1100~Hz, with the strongest modulation above 320~keV and a fractional amplitude of $\sim$47\%. Assuming the presence of a coherent periodic modulation, we use data-driven Monte Carlo simulations to place an upper limit of $\sim$8\% on the fraction of the total radiated energy that can be modulated by the QPO. This event, exhibiting a periodicity at $\sim$0.91~ms, further supports the possibility that millisecond periodicities can arise during GRBs in merger-driven scenarios.