Photospheric Emission From Variable Engine Gamma Ray Burst Simulations

TL;DR

This paper uses Monte Carlo radiation transfer coupled with hydrodynamic simulations to analyze photospheric emission in variable jet gamma-ray bursts, achieving good agreement with observed spectral properties and correlations.

Contribution

It introduces a novel application of the MCRaT code to variable jet profiles in GRB simulations, enhancing understanding of photospheric emission features.

Findings

Excellent match of time-resolved $eta$ parameters with observations.

Photospheric emission can produce the Band $eta$ parameter under certain conditions.

Simulations align with the Golenetskii correlation but show some discrepancies with the Amati and Yonetoku correlations.

Abstract

By coupling radiation transfer calculations to hydrodynamic simulations, there have been major advancements in understanding the long Gamma Ray Burst (LGRB) prompt emission. Building upon these achievements, we present an analysis of photospheric emission acquired by using the Monte Carlo Radiation Transfer (MCRaT) code on hydrodynamic simulations with variable jet profiles. MCRaT propagates and Compton scatters individual photons that have been injected into the collimated outflow in order to produce synthetic light curves and spectra. These light curves and spectra allow us to compare our results to LGRB observational data. We find excellent agreement between our fitted time resolved $\beta$ parameters and those that are observed. Additionally, our simulations show that photospheric emission, under certain conditions, is able to create the observationally expected Band $\alpha$ parameter. Finally, we show that the simulations are consistent with the Golenetskii correlation but exhibit some strain with the Amati and Yonetoku correlations.