Exploring Jet Structure and Dynamics in Short Gamma Ray Bursts: A Case Study on GRB 090510

TL;DR

This study uses GRMHD simulations to analyze the jet structure, energetics, and variability of the short GRB 090510, providing insights into its physical conditions and evolution.

Contribution

It introduces detailed 2D and 3D GRMHD models of GRB 090510, including ejecta effects, to better understand jet dynamics and observable properties.

Findings

Predicted energetics and jet opening angles match observations within 1σ.

Jet opening angles evolve with redshift, affecting observed properties.

Including dynamical ejecta influences jet collimation at small distances.

Abstract

Gamma-ray bursts observed in high-energies allow the investigation of the emission processes of these still puzzling events. In this study, we perform general relativistic magnetohydrodynamic (GRMHD) simulations to investigate GRB 090510, a peculiar short GRB detected by Fermi-LAT. Our primary goal is to model the energetics, jet structure, variability, and opening angle of the burst to understand its underlying physical conditions. We tested the 2D and 3D models and estimated the time scale of variability. The predicted energetics and the jet opening angle reconcile with the observed ones with 1$\sigma$ when considering that the jet opening angles also evolve with redshift. Furthermore, we extend our analysis by incorporating dynamical ejecta into selected models to study its impact on jet collimation at smaller distances. In addition, we investigated a suite of models exhibiting a broad range of observable GRB properties, thereby extending our understanding beyond this specific event.