  The angular dependence of emission in gamma-ray bursts (GRB) is of
fundamental importance in understanding the underlying physical mechanisms, as
well as in multimessenger search efforts. We examine the prospects of using
reconstructed GRB jet opening angles and off-axis observer angles in
determining the jet structure. We show that the reconstructed angles by Ryan et
al. (2015) are inconsistent with uniform jet structure. We further calculate
the number of GRBs with accurately reconstructed opening and observer angles
necessary to differentiate between some phenomenological non-uniform
structures.

High Energy Astrophysical Phenomena