A period-increasing oscillation signal in a long gamma-ray burst

TL;DR

This paper reports the discovery of a unique, increasing-period oscillation in a gamma-ray burst, suggesting new insights into the central engine's dynamics, possibly involving accretion disk precession caused by tidal disruption.

Contribution

It presents the first identification of a period-increasing oscillation in a GRB, providing new evidence for the behavior of the central engine during such events.

Findings

Detected a unique oscillation with increasing period from 1.27s to 4.02s

Suggests accretion disk precession as a possible cause

Opens new avenues for understanding GRB central engines

Abstract

Gamma-ray bursts (GRBs), the brightest electromagnetic bursts in the universe, are believed to originate from ultra-relativistic jets launched by the rapidly rotating central engine, either a disk-surrounded newly formed black hole (BH) or a magnetar. Such a central engine potentially possesses rapidly evolving physical characteristics, as it is just born. The caught of time-increasing frequency in the gravitational wave signals is the evidence of upon opinion. Here we report a possible oscillatory signal identified in GRB 131122B with periods increasing from 1.27 seconds to 4.02 seconds in a time interval of 16.75 seconds. Such a peculiar oscillation signal has not been identified in GRBs before and its periodic evolution could also be the quickest one found in the electromagnetic radiation window of astrophysics. The precession of a misaligned accretion disk caused by the tidal disruption of a star by an intermediate-mass BH may be responsible for this signal. This finding could open a new window to reveal the nature of the hiding central engine of GRBs.