A Turbulent Model of Gamma-Ray Burst Variability

TL;DR

This paper introduces a relativistically turbulent model for gamma-ray burst variability, explaining rapid lightcurve fluctuations through turbulence-induced eddy Lorentz factors, offering an alternative to the internal shock paradigm.

Contribution

The paper proposes a novel turbulent model for GRB variability, linking turbulence properties to observed lightcurve features and efficiency, differing from traditional internal shock models.

Findings

Model naturally produces highly variable lightcurves with multiple pulses.

Efficiency of energy conversion remains high despite inhomogeneity.

Pulse durations are consistent with observed GRB timescales.

Abstract

A popular paradigm to explain the rapid temporal variability observed in gamma-ray burst (GRB) lightcurves is the internal shock model. We propose an alternative model in which the radiating fluid in the GRB shell is relativistically turbulent with a typical eddy Lorentz factor $\gamma_t$. In this model, all pulses in the gamma-ray lightcurve are produced at roughly the same distance $R$ from the center of the explosion. The burst duration is $\sim R/c\Gamma^2$, where $\Gamma$ is the bulk Lorentz factor of the expanding shell, and the duration of individual pulses in the lightcurve is $\sim R/c\Gamma^2\gamma_t^2$. The model naturally produces highly variable lightcurves with $\sim\gamma_t^2$ individual pulses. Even though the model assumes highly inhomogeneous conditions, nevertheless the efficiency for converting jet energy to radiation is high.