Synchrotron Origin of the Typical GRB Band Function - A Case Study of GRB 130606B

TL;DR

This study demonstrates that the observed spectra of GRB 130606B can be explained by a time-dependent synchrotron radiation model, providing a natural physical origin for the typical Band function in gamma-ray bursts.

Contribution

It shows that a minimal physical synchrotron model with decaying magnetic fields can successfully fit GRB spectra traditionally described by empirical functions.

Findings

Successful fit of GRB 130606B spectra with synchrotron model

Synchrotron radiation can naturally produce Band-like spectra

Supports synchrotron origin for typical GRB spectra

Abstract

We perform a time-resolved spectral analysis of GRB 130606B within the framework of a fast-cooling synchrotron radiation model with magnetic field strength in the emission region decaying with time, as proposed by Uhm & Zhang. The data from all time intervals can be successfully fit by the model. The same data can be equally well fit by the empirical Band function with typical parameter values. Our results, which involve only minimal physical assumptions, offer one natural solution to the origin of the observed GRB spectra and imply that, at least some, if not all, Band-like GRB spectra with typical Band parameter values can indeed be explained by synchrotron radiation.