Neutrino Fluence from Gamma-Ray Bursts: Off-Axis View of Structured Jets

TL;DR

This paper develops a formalism to predict high-energy neutrino fluence from gamma-ray bursts viewed off-axis, accounting for jet structure and viewing angle, with implications for multi-messenger astronomy.

Contribution

It generalizes previous models to include arbitrary viewing angles and structured jets, providing an improved scaling relation for off-axis neutrino fluences.

Findings

Neutrino fluence can vary strongly with viewing angle.

Structured jets can produce more extended neutrino emission.

Application to GRB 170817A shows significant off-axis neutrino signals.

Abstract

We investigate the expected high-energy neutrino fluence from internal shocks produced in the relativistic outflow of gamma-ray bursts. Previous model predictions have primarily focussed on on-axis observations of uniform jets. Here we present a generalization to account for arbitrary viewing angles and jet structures. Based on this formalism, we provide an improved scaling relation that expresses off-axis neutrino fluences in terms of on-axis model predictions. We also find that the neutrino fluence from structured jets can exhibit a strong angular dependence relative to that of gamma-rays and can be far more extended. We examine this behavior in detail for the recent short gamma-ray burst GRB 170817A observed in coincidence with the gravitational wave event GW170817.