Spectral-Temporal Simulations of Internal Dissipation Models of Gamma-Ray Bursts

TL;DR

This paper develops a time-dependent simulation of gamma-ray burst spectra, capturing their evolution and explaining observed features like delayed GeV emissions through internal dissipation models.

Contribution

It introduces a new computational method for modeling gamma-ray burst spectra involving internal dissipation and external photon sources.

Findings

Models reproduce typical Band spectra and their evolution.

External photon sources can produce delayed GeV emissions.

Internal shocks alone partially explain observed delays.

Abstract

We present calculations of the time evolution of the prompt spectra of gamma-ray burst models involving generic internal dissipation regions, including internal shocks, either by itself or in the presence of an external photon source such as a photosphere. The method uses a newly developed time-dependent code involving synchrotron emission and absorption, inverse Compton scattering and pair formation. The models reproduce the typical observed Band spectra and their generic time evolution, including the appearance of an extra keV-GeV component, whose delay in simple SSC models, however, is only partially able to explain the several seconds observed GeV delays. On the other hand, models involving both a photosphere and an internal dissipation region at a larger radius produce both an extra GeV component and time delays which are in the range of the observations.