Fast optical variability of Naked-Eye Burst - manifestation of periodic activity of internal engine

TL;DR

This paper reports the discovery of rapid optical variability in the Naked-Eye Burst GRB080319B, linking it to the activity of the internal engine, likely a hyperaccreting black hole, through high-resolution imaging.

Contribution

It presents the first high-temporal-resolution optical imaging of a gamma-ray burst's prompt emission, revealing variability that reflects the internal engine's behavior.

Findings

Fast optical variability observed during the burst

Similarity between optical and gamma-ray temporal structures

Evidence supporting a black hole accretion engine

Abstract

We imaged the position of the Naked-Eye Burst, GRB080319B, before, during and after its gamma-ray activity with sub-second temporal resolution and discovered the fast variability of its prompt optical emission. Its characteristics and similarity with properties of gamma emission temporal structure suggest that it reflects the behaviour of internal engine -- supposedly, a hyperaccreting solar-mass black hole formed in the collapse of a massive stellar core.