Off-axis afterglow light curves and images from 2D hydrodynamic simulations of double-sided GRB jets in a stratified external medium

Understand

Gamma-ray burst (GRB) jets are narrow, and thus typically point away from us.

• They are initially ultra-relativistic, causing their prompt $\gamma$-ray and early afterglow emission to be beamed away from us.
• However, as the jet gradually decelerates its beaming cone widens and eventually reaches our line of sight and the afterglow emission may be detected.
• Such orphan afterglows were not clearly detected so far.