An Analysis of Chandra Deep Follow-up GRBs: Implications for Off-Axis Jets

TL;DR

This paper analyzes a sample of 27 GRBs with Swift and Chandra data, developing a numerical model that incorporates off-axis effects, lateral expansion, and edge effects to better understand jet breaks.

Contribution

It introduces a comprehensive numerical simulation model that accounts for off-axis effects, improving the interpretation of GRB jet breaks compared to previous models.

Findings

Off-axis effects are significant in GRB jet break analysis.

The model provides better fits to observed light curves.

Constraints on physical parameters of GRB jets are improved.

Abstract

We present a sample of 27 GRBs with detailed Swift light curves supplemented by late time Chandra observations. To answer the missing jet-break problem in general, we develop a numerical simulation based model which can be directly fit to the data using Monte Carlo methods. Our numerical model takes into account all the factors that can shape a jet-break: (i) lateral expansion (ii) edge effects and (iii) off-axis effects. Our results provide improved fits to the light curves and constraints on physical parameters. More importantly, our results suggest that off-axis effects are important and must be included in interpretations of GRB jet breaks.