Joint constraint on the jet structures from the short GRB population and GRB 170817A

TL;DR

This study examines jet structures of short gamma-ray bursts, especially GRB 170817A, by comparing afterglow and prompt emission data with population models, finding some models more consistent but with uncertainties remaining.

Contribution

It introduces a joint analysis of jet structures using both individual burst data and population distributions, constraining models with observational data.

Findings

Power-law and double-Gaussian models are somewhat favored over single-Gaussian.

Jet structure models can be consistent with both afterglow and prompt emission data.

Large uncertainties prevent definitive conclusions about the best jet structure model.

Abstract

The nearest GRB 170817A provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst (SGRB), by using its off-axis observed afterglow emission. It is investigated that whether the afterglow-constrained jet structures can be consistent with the luminosity of the prompt emission of GRB 170817A. Furthermore, by assuming that all SGRBs including GRB 170817A have the same explosive mechanism and jet structure, we apply the different jet structures to the calculation of the flux and redshift distributions of the SGRB population, confronting with the observational distributions of the Swift and Fermi sources. In comparison, it is found that the power-law and double-Gaussian models could be somewhat more favored than the single-Gaussian structure, as the last one could be not very consistent with the flux distribution of the Fermi data. Nevertheless, in view of the large uncertainty of parameters, we are still unable to make a sufficiently conclusive judgment at present.