Underlying global features of the x-ray light curves of {\it swift} gamma-ray bursts

TL;DR

This study analyzes 150 Swift GRBs' X-ray light curves, revealing global features like a steady plateau during prompt emission and a continuous evolution into afterglow, challenging existing models and suggesting a persistent central engine.

Contribution

It provides the first comprehensive analysis of global features in Swift GRB X-ray light curves, highlighting a steady plateau and continuous evolution that constrain theoretical models.

Findings

Discovery of a steady plateau in prompt X-ray emission.

Observation of a continuous power-law evolution from prompt to afterglow.

Distinct spectral behaviors indicating different radiation mechanisms.

Abstract

With its rapid response, {\it Swift} has revealed plenty of unexpected properties of gamma-ray bursts (GRBs). With an abundance of observations, our current understanding is only limited by complexity of early X-ray light curves. In this work, based on the public {\it Swift} data of 150 well-monitored GRBs with measured redshifts, we find some interesting global features in the rest-frame X-ray light curves. The distinct spectral behaviors between the prompt emission and the afterglow emission implies dissimilar radiation scenarios. Interestingly, an unforeseen plateau is exhibited in the prompt X-ray light curves despite the presence of complex spikes, which might indicate the presence of a steady central engine. In particular, the seemingly continuous evolution with a single power law from the prompt to the afterglow of most GRBs might place strong constraints on the theoretical models.