Quasi-Periodic Oscillations in Gamma-Ray Bursts' Prompt Light Curves

Abstract

I report on the discovery of 34 new quasi-periodic oscillations (QPOs) in the prompt light curves of long gamma-ray bursts (GRBs) from the Swift/BAT catalog: with one or more constant leading periods, as well as several chirping signals. This is the largest homogenously identified sample or GRB QPOs to date. The presence of QPOs suggests the existence of characteristic time scales that at least in some GRBs might be related to the dynamical properties of plasma trajectories in the accretion disks powering the relativistic jets. Several scenarios for their origin were examined. We identify non-planar orbits around Kerr black holes, the Lense-Thirring effect, and shock oscillations as plausible mechanisms for the QPO generation.